CppTools: Match also function arguments in locator

Useful when there are several overloads for the same function.

Change-Id: I325bda7d2fdf4108f71a61d5473cd55310c51c28
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

tests/cpplocators/testdata_basic/file1.cpp

@@ -12,8 +12,9 @@ int myVariable;
 
 int myFunction(bool yesno, int number) {}
 
+struct Pos {};
 void pointOfService() {}
-int getPosition() { return 0; }
+int matchArgument(Pos p) { return 0; }
 int positiveNumber() { return 2; }
 
 enum MyEnum { V1, V2 };