Add a diff to kpeg. CI should fail.

Author: tompng

lib/rdoc/markdown.kpeg

@@ -975,7 +975,7 @@ Str = @StartList:a
       < @NormalChar+ > { a = text }
       ( StrChunk:c { a << c } )* { a }
 
-StrChunk = < (@NormalChar | /_+/ &Alphanumeric)+ > { text }
+StrChunk = < (@NormalChar | /_+/ &Alphanumeric)+ > { text.itself }
 
 EscapedChar =   "\\" !@Newline < /[:\\`|*_{}\[\]()#+.!><-]/ > { text }