Add support for more complex command prompts (#583)

The bashsession lexer did only recognized command prompts starting with
one of the characters '#$%>'. This commit adds support for a prefixed
block of the form `[.*@.*]`, which is a common layout for command prompts.

Author: qtc-de

Diff for: lexers/b/bashsession.go

@@ -20,7 +20,7 @@ var BashSession = internal.Register(MustNewLazyLexer(
 func bashsessionRules() Rules {
 	return Rules{
 		"root": {
-			{`(^[#$%>]\s*)(.*\n?)`, ByGroups(GenericPrompt, Using(Bash)), nil},
+			{`^((?:\[[^]]+@[^]]+\]\s?)?[#$%>])(\s*)(.*\n?)`, ByGroups(GenericPrompt, Text, Using(Bash)), nil},
 			{`^.+\n?`, GenericOutput, nil},
 		},
 	}

Diff for: lexers/testdata/bashsession.actual

@@ -5,3 +5,11 @@ Hello, world!
 >  make -j build
 %ls | wc -l
 5
+[user@host]$ whoami
+user
+[user@host] # id
+uid=1000(user) gid=1000(user) groups=1000(user)
+[super user :D@super host :D] %if [ 1 -eq 1 ]; then uname; fi
+Linux
+[user@host]%echo $((1+1))
+2

Diff for: lexers/testdata/bashsession.expected

@@ -1,19 +1,56 @@
 [
-  {"type":"GenericPrompt","value":"$ "},
+  {"type":"GenericPrompt","value":"$"},
+  {"type":"Text","value":" "},
   {"type":"NameBuiltin","value":"echo"},
   {"type":"Text","value":" "},
   {"type":"LiteralStringDouble","value":"\"Hello, world!\""},
   {"type":"Text","value":"\n"},
   {"type":"GenericOutput","value":"Hello, world!\n"},
-  {"type":"GenericPrompt","value":"%\t"},
+  {"type":"GenericPrompt","value":"%"},
+  {"type":"Text","value":"\t"},
   {"type":"NameBuiltin","value":"pwd"},
   {"type":"Text","value":"\n"},
   {"type":"GenericOutput","value":"/User/foo\n"},
-  {"type":"GenericPrompt","value":">  "},
-  {"type":"Text","value":"make -j build\n"},
+  {"type":"GenericPrompt","value":"\u003e"},
+  {"type":"Text","value":"  make -j build\n"},
   {"type":"GenericPrompt","value":"%"},
   {"type":"Text","value":"ls "},
   {"type":"Punctuation","value":"|"},
   {"type":"Text","value":" wc -l\n"},
-  {"type":"GenericOutput","value":"5\n"}
+  {"type":"GenericOutput","value":"5\n"},
+  {"type":"GenericPrompt","value":"[user@host]$"},
+  {"type":"Text","value":" whoami\n"},
+  {"type":"GenericOutput","value":"user\n"},
+  {"type":"GenericPrompt","value":"[user@host] #"},
+  {"type":"Text","value":" id\n"},
+  {"type":"GenericOutput","value":"uid=1000(user) gid=1000(user) groups=1000(user)\n"},
+  {"type":"GenericPrompt","value":"[super user :D@super host :D] %"},
+  {"type":"Keyword","value":"if"},
+  {"type":"Text","value":" "},
+  {"type":"Operator","value":"["},
+  {"type":"Text","value":" "},
+  {"type":"LiteralNumber","value":"1"},
+  {"type":"Text","value":" -eq "},
+  {"type":"LiteralNumber","value":"1"},
+  {"type":"Text","value":" "},
+  {"type":"Operator","value":"]"},
+  {"type":"Punctuation","value":";"},
+  {"type":"Text","value":" "},
+  {"type":"Keyword","value":"then"},
+  {"type":"Text","value":" uname"},
+  {"type":"Punctuation","value":";"},
+  {"type":"Text","value":" "},
+  {"type":"Keyword","value":"fi"},
+  {"type":"Text","value":"\n"},
+  {"type":"GenericOutput","value":"Linux\n"},
+  {"type":"GenericPrompt","value":"[user@host]%"},
+  {"type":"NameBuiltin","value":"echo"},
+  {"type":"Text","value":" "},
+  {"type":"Keyword","value":"$(("},
+  {"type":"LiteralNumber","value":"1"},
+  {"type":"Operator","value":"+"},
+  {"type":"LiteralNumber","value":"1"},
+  {"type":"Keyword","value":"))"},
+  {"type":"Text","value":"\n"},
+  {"type":"GenericOutput","value":"2\n"}
 ]