Squashed commit of the following:

commit 95479c8ad744db48386a5c78e54ef8da80e9120b
Author: Chris Lane <chris@chris-allen-lane.com>
Date:   Wed Apr 28 12:26:32 2021 -0400

    chore(version): bump version to 4.2.1

commit 6956f51cae
Author: Chris Lane <chris@chris-allen-lane.com>
Date:   Wed Apr 28 12:24:21 2021 -0400

    fix(Makefile): `vendor-update`

    Update the `vendor-update` build target to run `go mod vendor` after
    updating dependencies.

commit 0aca411279
Author: Chris Lane <chris@chris-allen-lane.com>
Date:   Wed Apr 28 12:23:24 2021 -0400

    chore(deps): update dependencies

commit e847956b02
Author: Chris Lane <chris@chris-allen-lane.com>
Date:   Wed Apr 28 08:26:51 2021 -0400

    chore(deps): build updates

    - Upgrade `go` to `1.16.3`

    - Attempt to fix build errors regarding dependencies

vendor/github.com/alecthomas/chroma/lexers/r/r.go

@@ -6,14 +6,18 @@ import (
 )
 
 // R/S lexer.
-var R = internal.Register(MustNewLexer(
+var R = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "R",
 		Aliases:   []string{"splus", "s", "r"},
 		Filenames: []string{"*.S", "*.R", "*.r", ".Rhistory", ".Rprofile", ".Renviron"},
 		MimeTypes: []string{"text/S-plus", "text/S", "text/x-r-source", "text/x-r", "text/x-R", "text/x-r-history", "text/x-r-profile"},
 	},
-	Rules{
+	rRules,
+))
+
+func rRules() Rules {
+	return Rules{
 		"comments": {
 			{`#.*$`, CommentSingle, nil},
 		},
@@ -62,5 +66,5 @@ var R = internal.Register(MustNewLexer(
 		"string_dquote": {
 			{`([^"\\]|\\.)*"`, LiteralString, Pop(1)},
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/r/racket.go

@@ -6,14 +6,18 @@ import (
 )
 
 // Racket lexer.
-var Racket = internal.Register(MustNewLexer(
+var Racket = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "Racket",
 		Aliases:   []string{"racket", "rkt"},
 		Filenames: []string{"*.rkt", "*.rktd", "*.rktl"},
 		MimeTypes: []string{"text/x-racket", "application/x-racket"},
 	},
-	Rules{
+	racketRules,
+))
+
+func racketRules() Rules {
+	return Rules{
 		"root": {
 			{`[)\]}]`, Error, nil},
 			{`(?!\Z)`, Text, Push("unquoted-datum")},
@@ -98,5 +102,5 @@ var Racket = internal.Register(MustNewLexer(
 			{`(?s)\\([0-7]{1,3}|x[\da-fA-F]{1,2}|u[\da-fA-F]{1,4}|U[\da-fA-F]{1,8}|.)`, LiteralStringEscape, nil},
 			{`[^\\"]+`, LiteralStringDouble, nil},
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/r/ragel.go

@@ -6,14 +6,18 @@ import (
 )
 
 // Ragel lexer.
-var Ragel = internal.Register(MustNewLexer(
+var Ragel = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "Ragel",
 		Aliases:   []string{"ragel"},
 		Filenames: []string{},
 		MimeTypes: []string{},
 	},
-	Rules{
+	ragelRules,
+))
+
+func ragelRules() Rules {
+	return Rules{
 		"whitespace": {
 			{`\s+`, TextWhitespace, nil},
 		},
@@ -72,5 +76,5 @@ var Ragel = internal.Register(MustNewLexer(
 			{`\{`, Punctuation, Push()},
 			{`\}`, Punctuation, Pop(1)},
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/r/reasonml.go

@@ -6,14 +6,18 @@ import (
 )
 
 // Reasonml lexer.
-var Reasonml = internal.Register(MustNewLexer(
+var Reasonml = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "ReasonML",
 		Aliases:   []string{"reason", "reasonml"},
 		Filenames: []string{"*.re", "*.rei"},
 		MimeTypes: []string{"text/x-reasonml"},
 	},
-	Rules{
+	reasonmlRules,
+))
+
+func reasonmlRules() Rules {
+	return Rules{
 		"escape-sequence": {
 			{`\\[\\"\'ntbr]`, LiteralStringEscape, nil},
 			{`\\[0-9]{3}`, LiteralStringEscape, nil},
@@ -63,5 +67,5 @@ var Reasonml = internal.Register(MustNewLexer(
 			{`[a-z_][\w\']*`, Name, Pop(1)},
 			Default(Pop(1)),
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/r/regedit.go

@@ -6,14 +6,18 @@ import (
 )
 
 // Reg lexer.
-var Reg = internal.Register(MustNewLexer(
+var Reg = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "reg",
 		Aliases:   []string{"registry"},
 		Filenames: []string{"*.reg"},
 		MimeTypes: []string{"text/x-windows-registry"},
 	},
-	Rules{
+	regRules,
+))
+
+func regRules() Rules {
+	return Rules{
 		"root": {
 			{`Windows Registry Editor.*`, Text, nil},
 			{`\s+`, Text, nil},
@@ -28,5 +32,5 @@ var Reg = internal.Register(MustNewLexer(
 			{`.+`, LiteralString, Pop(1)},
 			Default(Pop(1)),
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/r/rexx.go

@@ -6,7 +6,7 @@ import (
 )
 
 // Rexx lexer.
-var Rexx = internal.Register(MustNewLexer(
+var Rexx = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:            "Rexx",
 		Aliases:         []string{"rexx", "arexx"},
@@ -15,7 +15,11 @@ var Rexx = internal.Register(MustNewLexer(
 		NotMultiline:    true,
 		CaseInsensitive: true,
 	},
-	Rules{
+	rexxRules,
+))
+
+func rexxRules() Rules {
+	return Rules{
 		"root": {
 			{`\s`, TextWhitespace, nil},
 			{`/\*`, CommentMultiline, Push("comment")},
@@ -55,5 +59,5 @@ var Rexx = internal.Register(MustNewLexer(
 			{`\*/`, CommentMultiline, Pop(1)},
 			{`\*`, CommentMultiline, nil},
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/r/rst.go

@@ -8,14 +8,18 @@ import (
 )
 
 // Restructuredtext lexer.
-var Restructuredtext = internal.Register(MustNewLexer(
+var Restructuredtext = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "reStructuredText",
 		Aliases:   []string{"rst", "rest", "restructuredtext"},
 		Filenames: []string{"*.rst", "*.rest"},
 		MimeTypes: []string{"text/x-rst", "text/prs.fallenstein.rst"},
 	},
-	Rules{
+	restructuredtextRules,
+))
+
+func restructuredtextRules() Rules {
+	return Rules{
 		"root": {
 			{"^(=+|-+|`+|:+|\\.+|\\'+|\"+|~+|\\^+|_+|\\*+|\\++|#+)([ \\t]*\\n)(.+)(\\n)(\\1)(\\n)", ByGroups(GenericHeading, Text, GenericHeading, Text, GenericHeading, Text), nil},
 			{"^(\\S.*)(\\n)(={3,}|-{3,}|`{3,}|:{3,}|\\.{3,}|\\'{3,}|\"{3,}|~{3,}|\\^{3,}|_{3,}|\\*{3,}|\\+{3,}|#{3,})(\\n)", ByGroups(GenericHeading, Text, GenericHeading, Text), nil},
@@ -56,8 +60,8 @@ var Restructuredtext = internal.Register(MustNewLexer(
 			{"``((?=$)|(?=[-/:.,; \\n\\x00\\\u2010\\\u2011\\\u2012\\\u2013\\\u2014\\\u00a0\\'\\\"\\)\\]\\}\\>\\\u2019\\\u201d\\\u00bb\\!\\?]))", LiteralString, Pop(1)},
 			{"`", LiteralString, nil},
 		},
-	},
-))
+	}
+}
 
 func rstCodeBlock(groups []string, lexer Lexer) Iterator {
 	iterators := []Iterator{}

vendor/github.com/alecthomas/chroma/lexers/r/ruby.go

@@ -6,7 +6,7 @@ import (
 )
 
 // Ruby lexer.
-var Ruby = internal.Register(MustNewLexer(
+var Ruby = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "Ruby",
 		Aliases:   []string{"rb", "ruby", "duby"},
@@ -14,7 +14,11 @@ var Ruby = internal.Register(MustNewLexer(
 		MimeTypes: []string{"text/x-ruby", "application/x-ruby"},
 		DotAll:    true,
 	},
-	Rules{
+	rubyRules,
+))
+
+func rubyRules() Rules {
+	return Rules{
 		"root": {
 			{`\A#!.+?$`, CommentHashbang, nil},
 			{`#.*?$`, CommentSingle, nil},
@@ -39,7 +43,7 @@ var Ruby = internal.Register(MustNewLexer(
 			{`(0_?[0-7]+(?:_[0-7]+)*)(\s*)([/?])?`, ByGroups(LiteralNumberOct, Text, Operator), nil},
 			{`(0x[0-9A-Fa-f]+(?:_[0-9A-Fa-f]+)*)(\s*)([/?])?`, ByGroups(LiteralNumberHex, Text, Operator), nil},
 			{`(0b[01]+(?:_[01]+)*)(\s*)([/?])?`, ByGroups(LiteralNumberBin, Text, Operator), nil},
-			{`([\d]+(?:_\d+)*)(\s*)([/?])?`, ByGroups(LiteralNumberInteger, Text, Operator), nil},
+			{`([\d]+(?:[_e]\d+)*)(\s*)([/?])?`, ByGroups(LiteralNumberInteger, Text, Operator), nil},
 			{`@@[a-zA-Z_]\w*`, NameVariableClass, nil},
 			{`@[a-zA-Z_]\w*`, NameVariableInstance, nil},
 			{`\$\w+`, NameVariableGlobal, nil},
@@ -246,5 +250,5 @@ var Ruby = internal.Register(MustNewLexer(
 			{`[\\#<>]`, LiteralStringRegex, nil},
 			{`[^\\#<>]+`, LiteralStringRegex, nil},
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/r/rust.go

@@ -6,7 +6,7 @@ import (
 )
 
 // Rust lexer.
-var Rust = internal.Register(MustNewLexer(
+var Rust = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "Rust",
 		Aliases:   []string{"rust"},
@@ -14,7 +14,11 @@ var Rust = internal.Register(MustNewLexer(
 		MimeTypes: []string{"text/rust"},
 		EnsureNL:  true,
 	},
-	Rules{
+	rustRules,
+))
+
+func rustRules() Rules {
+	return Rules{
 		"root": {
 			{`#![^[\r\n].*$`, CommentPreproc, nil},
 			Default(Push("base")),
@@ -131,5 +135,5 @@ var Rust = internal.Register(MustNewLexer(
 			{`\);?`, CommentPreproc, Pop(1)},
 			{`[^")]+`, CommentPreproc, nil},
 		},
-	},
-))
+	}
+}