Fix some Perl functions not being recognized in function list issue

Fix Perl functions without parentheses / with attributes are not recognized in function list issue.

Fix #4265, close #4266

PowerEditor/Test/FunctionList/perl/unitTest

@@ -148,6 +148,10 @@ sub VarNames($)
     return (@vars);
 }
 
+sub functionNoParentheses {
+    return 1
+}
+
 ############### Start ###############
 
 print "\npltags $VERSION by Michael Schaap <mscha\@mscha.com>\n\n";

PowerEditor/Test/FunctionList/perl/unitTest.expected.result

@@ -1 +1 @@
-{"leaves":["MakeTag","PackageName","SubName","VarNames"],"root":"unitTest"}
+{"leaves":["MakeTag","PackageName","SubName","VarNames","functionNoParentheses"],"root":"unitTest"}

PowerEditor/src/functionList.xml

@@ -651,10 +651,8 @@
 							sub
 							\s+
 							[A-Za-z_]\w*
-							\s*
-							\(
-							[^()]*
-							\)
+							(\s*\([^()]*\))?                                    # prototype or signature
+						  	(\s*\:\s*[^{]+)?                                    # attributes
 							\s*\{                                               # start of class body
 						"
 				>