Fix trailing-comma errors on method calls

We were only matching `f(a, ` patterns, and not `x:f(a, `. We now just
match against any usages of call_args - hadn't quite realised we could
do that!

projects/core/src/test/resources/test-rom/spec/modules/cc/internal/syntax/parser_spec.md

@@ -478,6 +478,7 @@ ## Additional commas
  1 | f(2, )
    |    ^ Tip: Try removing this ,.
 ```
+
 ```lua
 f(2, 3, )
 ```
@@ -491,3 +492,17 @@ ## Additional commas
  1 | f(2, 3, )
    |       ^ Tip: Try removing this ,.
 ```
+
+```lua
+x:f(2, 3, )
+```
+
+```txt
+Unexpected ) in function call.
+   |
+ 1 | x:f(2, 3, )
+   |           ^
+   |
+ 1 | x:f(2, 3, )
+   |         ^ Tip: Try removing this ,.
+```