[sh] Allow more characters in aliases and function names

Which characters are allowed?
- Aliases: https://www.gnu.org/software/bash/manual/html_node/Aliases.html
- Functions: https://unix.stackexchange.com/questions/245331/shell-valid-function-name-characters

For aliases I chose [\w-.] instead of blacklisting many forbidden characters. For functions I chose \S.

rc/filetype/sh.kak

@@ -56,7 +56,8 @@ evaluate-commands %sh{
 
 add-highlighter shared/sh/code/operators regex [\[\]\(\)&|]{1,2} 0:operator
 add-highlighter shared/sh/code/variable regex ((?<![-:])\b\w+)= 1:variable
-add-highlighter shared/sh/code/function regex ^\h*(\w+)\h*\(\) 1:function
+add-highlighter shared/sh/code/alias regex \balias(\h+[-+]\w)*\h+([\w-.]+)= 2:variable
+add-highlighter shared/sh/code/function regex ^\h*(\S+)\h*\(\) 1:function
 
 add-highlighter shared/sh/code/unscoped_expansion regex \$(\w+|#|@|\?|\$|!|-|\*) 0:value
 add-highlighter shared/sh/double_string/expansion regex \$(\w+|\{.+?\}) 0:value