2311: See through Macros for SignatureHelp r=matklad a=kjeremy
Note: we meed to skip the trivia filter to make sure that
`covers!(call_info_bad_offset)` succeeds otherwise we exit call_info
too early.
Also the test doesn't pass: `FnCallNode::with_node` always detects
a MacroCall which is obviously wrong.
Fixes#2310
Co-authored-by: kjeremy <kjeremy@gmail.com>
Co-authored-by: Jeremy Kolb <kjeremy@gmail.com>