add: Nujucks language

Author: hhatto

language.go

@@ -186,6 +186,7 @@ var Exts = map[string]string{
 	"m4":          "M4",
 	"l":           "lex",
 	"nim":         "Nim",
+	"njk":         "Nujucks",
 	"php":         "PHP",
 	"pas":         "Pascal",
 	"PL":          "Perl",
@@ -512,6 +513,7 @@ func NewDefinedLanguages() *DefinedLanguages {
 			"Mustache":            NewLanguage("Mustache", []string{}, [][]string{{"{{!", "}}"}}),
 			"M4":                  NewLanguage("M4", []string{"#"}, [][]string{{"", ""}}),
 			"Nim":                 NewLanguage("Nim", []string{"#"}, [][]string{{"#[", "]#"}}),
+			"Nunjucks":            NewLanguage("Nunjucks", []string{"{#"}, [][]string{{"{#", "#}"}, {"<!--", "-->"}}),
 			"lex":                 NewLanguage("lex", []string{}, [][]string{{"/*", "*/"}}),
 			"PHP":                 NewLanguage("PHP", []string{"#", "//"}, [][]string{{"/*", "*/"}}),
 			"Pascal":              NewLanguage("Pascal", []string{"//"}, [][]string{{"{", ")"}}),