Fallback to HTML lexer for Markdown text.

Fixes #321.

lexers/m/markdown.go

@@ -2,11 +2,12 @@ package m
 
 import (
 	. "github.com/alecthomas/chroma" // nolint
+	"github.com/alecthomas/chroma/lexers/h"
 	"github.com/alecthomas/chroma/lexers/internal"
 )
 
 // Markdown lexer.
-var Markdown = internal.Register(MustNewLexer(
+var Markdown = internal.Register(DelegatingLexer(h.HTML, MustNewLexer(
 	&Config{
 		Name:      "markdown",
 		Aliases:   []string{"md", "mkd"},
@@ -40,8 +41,8 @@ var Markdown = internal.Register(MustNewLexer(
 			{"`[^`]+`", LiteralStringBacktick, nil},
 			{`[@#][\w/:]+`, NameEntity, nil},
 			{`(!?\[)([^]]+)(\])(\()([^)]+)(\))`, ByGroups(Text, NameTag, Text, Text, NameAttribute, Text), nil},
-			{`[^\\\s]+`, Text, nil},
-			{`.|\n`, Text, nil},
+			{`[^\\\s]+`, Other, nil},
+			{`.|\n`, Other, nil},
 		},
 	},
-))
+)))

lexers/testdata/markdown.actual

@@ -1,5 +1,7 @@
 # about
 
+<div class="html">HTML</div>
+
 Multiple **bold** on the **same line**.
 
 ## user defined function in cql

lexers/testdata/markdown.expected

@@ -1,6 +1,18 @@
 [
   {"type":"GenericHeading","value":"# about\n"},
-  {"type":"Text","value":"\nMultiple "},
+  {"type":"Text","value":"\n"},
+  {"type":"Punctuation","value":"\u003c"},
+  {"type":"NameTag","value":"div"},
+  {"type":"Text","value":" "},
+  {"type":"NameAttribute","value":"class"},
+  {"type":"Operator","value":"="},
+  {"type":"LiteralString","value":"\"html\""},
+  {"type":"Punctuation","value":"\u003e"},
+  {"type":"Text","value":"HTML"},
+  {"type":"Punctuation","value":"\u003c/"},
+  {"type":"NameTag","value":"div"},
+  {"type":"Punctuation","value":"\u003e"},
+  {"type":"Text","value":"\n\nMultiple "},
   {"type":"GenericStrong","value":"**bold**"},
   {"type":"Text","value":" on the "},
   {"type":"GenericStrong","value":"**same line**"},