Remove whitespace tokenizing rule in markdown lexer (#1008)

fix #744 
related issue: go-gitea/gitea#32136

current markdown lexer is tokenizing by whitespace, but in markdown
sytanx this implementation can cause some errors.

Author: cloudchamb3r

lexers/markdown.go

@@ -40,7 +40,6 @@ func markdownRules() Rules {
 			{"`[^`]+`", LiteralStringBacktick, nil},
 			{`[@#][\w/:]+`, NameEntity, nil},
 			{`(!?\[)([^]]+)(\])(\()([^)]+)(\))`, ByGroups(Text, NameTag, Text, Text, NameAttribute, Text), nil},
-			{`[^\\\s]+`, Other, nil},
 			{`.|\n`, Other, nil},
 		},
 	}

lexers/testdata/markdown.actual

@@ -85,3 +85,9 @@ end loop;
 end
 $$;
 ```
+
+## MarkdownLink Test
+[normal link](https://google.com)  
+  [whitespace before link](https://google.com)  
+abc[non-whitespace before link](https://google.com)  
+([first link](https://google.com) and [second link](https://google.com))  

lexers/testdata/markdown.expected

@@ -441,5 +441,27 @@
   {"type":"Punctuation","value":";"},
   {"type":"Text","value":"\n"},
   {"type":"LiteralString","value":"```"},
-  {"type":"Text","value":"\n"}
+  {"type":"Text","value":"\n\n"},
+  {"type":"GenericSubheading","value":"## MarkdownLink Test\n"},
+  {"type":"Text","value":"["},
+  {"type":"NameTag","value":"normal link"},
+  {"type":"Text","value":"]("},
+  {"type":"NameAttribute","value":"https://google.com"},
+  {"type":"Text","value":")  \n  ["},
+  {"type":"NameTag","value":"whitespace before link"},
+  {"type":"Text","value":"]("},
+  {"type":"NameAttribute","value":"https://google.com"},
+  {"type":"Text","value":")  \nabc["},
+  {"type":"NameTag","value":"non-whitespace before link"},
+  {"type":"Text","value":"]("},
+  {"type":"NameAttribute","value":"https://google.com"},
+  {"type":"Text","value":")  \n(["},
+  {"type":"NameTag","value":"first link"},
+  {"type":"Text","value":"]("},
+  {"type":"NameAttribute","value":"https://google.com"},
+  {"type":"Text","value":") and ["},
+  {"type":"NameTag","value":"second link"},
+  {"type":"Text","value":"]("},
+  {"type":"NameAttribute","value":"https://google.com"},
+  {"type":"Text","value":"))  \n"}
 ]