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/d/d.go

@@ -6,7 +6,7 @@ import (
 )
 
 // D lexer. https://dlang.org/spec/lex.html
-var D = internal.Register(MustNewLexer(
+var D = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "D",
 		Aliases:   []string{"d"},
@@ -14,7 +14,11 @@ var D = internal.Register(MustNewLexer(
 		MimeTypes: []string{"text/x-d"},
 		EnsureNL:  true,
 	},
-	Rules{
+	dRules,
+))
+
+func dRules() Rules {
+	return Rules{
 		"root": {
 			{`[^\S\n]+`, Text, nil},
 
@@ -65,5 +69,5 @@ var D = internal.Register(MustNewLexer(
 		"import": {
 			{`[\w.]+\*?`, NameNamespace, Pop(1)},
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/d/dart.go

@@ -6,7 +6,7 @@ import (
 )
 
 // Dart lexer.
-var Dart = internal.Register(MustNewLexer(
+var Dart = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "Dart",
 		Aliases:   []string{"dart"},
@@ -14,7 +14,11 @@ var Dart = internal.Register(MustNewLexer(
 		MimeTypes: []string{"text/x-dart"},
 		DotAll:    true,
 	},
-	Rules{
+	dartRules,
+))
+
+func dartRules() Rules {
+	return Rules{
 		"root": {
 			Include("string_literal"),
 			{`#!(.*?)$`, CommentPreproc, nil},
@@ -87,5 +91,5 @@ var Dart = internal.Register(MustNewLexer(
 			Include("string_common"),
 			{`(\$|\')+`, LiteralStringSingle, nil},
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/d/diff.go

@@ -6,7 +6,7 @@ import (
 )
 
 // Diff lexer.
-var Diff = internal.Register(MustNewLexer(
+var Diff = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "Diff",
 		Aliases:   []string{"diff", "udiff"},
@@ -14,7 +14,11 @@ var Diff = internal.Register(MustNewLexer(
 		Filenames: []string{"*.diff", "*.patch"},
 		MimeTypes: []string{"text/x-diff", "text/x-patch"},
 	},
-	Rules{
+	diffRules,
+))
+
+func diffRules() Rules {
+	return Rules{
 		"root": {
 			{` .*\n`, Text, nil},
 			{`\+.*\n`, GenericInserted, nil},
@@ -25,5 +29,5 @@ var Diff = internal.Register(MustNewLexer(
 			{`=.*\n`, GenericHeading, nil},
 			{`.*\n`, Text, nil},
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/d/django.go

@@ -6,7 +6,7 @@ import (
 )
 
 // Django/Jinja lexer.
-var DjangoJinja = internal.Register(MustNewLexer(
+var DjangoJinja = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "Django/Jinja",
 		Aliases:   []string{"django", "jinja"},
@@ -14,7 +14,11 @@ var DjangoJinja = internal.Register(MustNewLexer(
 		MimeTypes: []string{"application/x-django-templating", "application/x-jinja"},
 		DotAll:    true,
 	},
-	Rules{
+	djangoJinjaRules,
+))
+
+func djangoJinjaRules() Rules {
+	return Rules{
 		"root": {
 			{`[^{]+`, Other, nil},
 			{`\{\{`, CommentPreproc, Push("var")},
@@ -49,5 +53,5 @@ var DjangoJinja = internal.Register(MustNewLexer(
 			Include("varnames"),
 			{`.`, Punctuation, nil},
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/d/docker.go

@@ -8,7 +8,7 @@ import (
 )
 
 // Docker lexer.
-var Docker = internal.Register(MustNewLexer(
+var Docker = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:            "Docker",
 		Aliases:         []string{"docker", "dockerfile"},
@@ -16,7 +16,11 @@ var Docker = internal.Register(MustNewLexer(
 		MimeTypes:       []string{"text/x-dockerfile-config"},
 		CaseInsensitive: true,
 	},
-	Rules{
+	dockerRules,
+))
+
+func dockerRules() Rules {
+	return Rules{
 		"root": {
 			{`#.*`, Comment, nil},
 			{`(ONBUILD)((?:\s*\\?\s*))`, ByGroups(Keyword, Using(b.Bash)), nil},
@@ -27,5 +31,5 @@ var Docker = internal.Register(MustNewLexer(
 			{`((?:RUN|CMD|ENTRYPOINT|ENV|ARG|LABEL|ADD|COPY))`, Keyword, nil},
 			{`(.*\\\n)*.+`, Using(b.Bash), nil},
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/d/dtd.go

@@ -6,7 +6,7 @@ import (
 )
 
 // Dtd lexer.
-var Dtd = internal.Register(MustNewLexer(
+var Dtd = internal.Register(MustNewLazyLexer(
 	&Config{
 		Name:      "DTD",
 		Aliases:   []string{"dtd"},
@@ -14,7 +14,11 @@ var Dtd = internal.Register(MustNewLexer(
 		MimeTypes: []string{"application/xml-dtd"},
 		DotAll:    true,
 	},
-	Rules{
+	dtdRules,
+))
+
+func dtdRules() Rules {
+	return Rules{
 		"root": {
 			Include("common"),
 			{`(<!ELEMENT)(\s+)(\S+)`, ByGroups(Keyword, Text, NameTag), Push("element")},
@@ -65,5 +69,5 @@ var Dtd = internal.Register(MustNewLexer(
 			{`[^>\s|()?+*,]+`, NameAttribute, nil},
 			{`>`, Keyword, Pop(1)},
 		},
-	},
-))
+	}
+}

vendor/github.com/alecthomas/chroma/lexers/d/dylan.go

@@ -0,0 +1,74 @@
+package d
+
+import (
+	. "github.com/alecthomas/chroma" // nolint
+	"github.com/alecthomas/chroma/lexers/internal"
+)
+
+// Dylan lexer.
+var Dylan = internal.Register(MustNewLexer(
+	&Config{
+		Name:            "Dylan",
+		Aliases:         []string{"dylan"},
+		Filenames:       []string{"*.dylan", "*.dyl", "*.intr"},
+		MimeTypes:       []string{"text/x-dylan"},
+		CaseInsensitive: true,
+	},
+	Rules{
+		"root": {
+			{`\s+`, Whitespace, nil},
+			{`//.*?\n`, CommentSingle, nil},
+			{`([a-z0-9-]+:)([ \t]*)(.*(?:\n[ \t].+)*)`, ByGroups(NameAttribute, Whitespace, LiteralString), nil},
+			Default(Push("code")),
+		},
+		"code": {
+			{`\s+`, Whitespace, nil},
+			{`//.*?\n`, CommentSingle, nil},
+			{`/\*`, CommentMultiline, Push("comment")},
+			{`"`, LiteralString, Push("string")},
+			{`'(\\.|\\[0-7]{1,3}|\\x[a-f0-9]{1,2}|[^\\\'\n])'`, LiteralStringChar, nil},
+			{`#b[01]+`, LiteralNumberBin, nil},
+			{`#o[0-7]+`, LiteralNumberOct, nil},
+			{`[-+]?(\d*\.\d+([ed][-+]?\d+)?|\d+(\.\d*)?e[-+]?\d+)`, LiteralNumberFloat, nil},
+			{`[-+]?\d+`, LiteralNumberInteger, nil},
+			{`#x[0-9a-f]+`, LiteralNumberHex, nil},
+
+			{`(\?\\?)([\w!&*<>|^$%@+~?/=-]+)(:)(token|name|variable|expression|body|case-body|\*)`,
+				ByGroups(Operator, NameVariable, Operator, NameBuiltin), nil},
+			{`(\?)(:)(token|name|variable|expression|body|case-body|\*)`,
+				ByGroups(Operator, Operator, NameVariable), nil},
+			{`(\?\\?)([\w!&*<>|^$%@+~?/=-]+)`, ByGroups(Operator, NameVariable), nil},
+
+			{`(=>|::|#\(|#\[|##|\?\?|\?=|\?|[(){}\[\],.;])`, Punctuation, nil},
+			{`:=`, Operator, nil},
+			{`#[tf]`, Literal, nil},
+			{`#"`, LiteralStringSymbol, Push("symbol")},
+			{`#[a-z0-9-]+`, Keyword, nil},
+			{`#(all-keys|include|key|next|rest)`, Keyword, nil},
+			{`[\w!&*<>|^$%@+~?/=-]+:`, KeywordConstant, nil},
+			{`<[\w!&*<>|^$%@+~?/=-]+>`, NameClass, nil},
+			{`\*[\w!&*<>|^$%@+~?/=-]+\*`, NameVariableGlobal, nil},
+			{`\$[\w!&*<>|^$%@+~?/=-]+`, NameConstant, nil},
+			{`(let|method|function)([ \t]+)([\w!&*<>|^$%@+~?/=-]+)`, ByGroups(NameBuiltin, Whitespace, NameVariable), nil},
+			{`(error|signal|return|break)`, NameException, nil},
+			{`(\\?)([\w!&*<>|^$%@+~?/=-]+)`, ByGroups(Operator, Name), nil},
+		},
+		"comment": {
+			{`[^*/]`, CommentMultiline, nil},
+			{`/\*`, CommentMultiline, Push()},
+			{`\*/`, CommentMultiline, Pop(1)},
+			{`[*/]`, CommentMultiline, nil},
+		},
+		"symbol": {
+			{`"`, LiteralStringSymbol, Pop(1)},
+			{`[^\\"]+`, LiteralStringSymbol, nil},
+		},
+		"string": {
+			{`"`, LiteralString, Pop(1)},
+			{`\\([\\abfnrtv"\']|x[a-f0-9]{2,4}|[0-7]{1,3})`, LiteralStringEscape, nil},
+			{`[^\\"\n]+`, LiteralString, nil},
+			{`\\\n`, LiteralString, nil},
+			{`\\`, LiteralString, nil},
+		},
+	},
+))