Add vendor files for go build

vendor/github.com/alecthomas/chroma/lexers/b/brainfuck.go

@@ -0,0 +1,34 @@
+package b
+
+import (
+	. "github.com/alecthomas/chroma" // nolint
+	"github.com/alecthomas/chroma/lexers/internal"
+)
+
+// Brainfuck lexer.
+var Brainfuck = internal.Register(MustNewLexer(
+	&Config{
+		Name:      "Brainfuck",
+		Aliases:   []string{"brainfuck", "bf"},
+		Filenames: []string{"*.bf", "*.b"},
+		MimeTypes: []string{"application/x-brainfuck"},
+	},
+	Rules{
+		"common": {
+			{`[.,]+`, NameTag, nil},
+			{`[+-]+`, NameBuiltin, nil},
+			{`[<>]+`, NameVariable, nil},
+			{`[^.,+\-<>\[\]]+`, Comment, nil},
+		},
+		"root": {
+			{`\[`, Keyword, Push("loop")},
+			{`\]`, Error, nil},
+			Include("common"),
+		},
+		"loop": {
+			{`\[`, Keyword, Push()},
+			{`\]`, Keyword, Pop(1)},
+			Include("common"),
+		},
+	},
+))