Add bang as a valid char for function names

src/ShellCheck/Parser.hs

@@ -67,7 +67,7 @@ doubleQuote = char '"'
 variableStart = upper <|> lower <|> oneOf "_"
 variableChars = upper <|> lower <|> digit <|> oneOf "_"
 -- Chars to allow in function names
-functionChars = variableChars <|> oneOf ":+?-./^@,"
+functionChars = variableChars <|> oneOf "#:+?-./^@,"
 -- Chars to allow in functions using the 'function' keyword
 extendedFunctionChars = functionChars <|> oneOf "[]*=!"
 specialVariable = oneOf (concat specialVariables)