* test: add failing idempotency tests for commented-out RSX blocks
Two variants of the regression introduced in v0.7.4 (#5257):
- commented_rsx_block: first line keeps indent, rest gets dedented
- commented_rsx_block_nested: entire block gets dedented
See #5463
* fix(autofmt): preserve indentation of commented-out RSX blocks
Trailing comments before `}` in write_rsx_block were indented at
parent level instead of child level. Truncate the tab from
tabbed_line() and bump indent to child level before
apply_line_comments, same approach as write_trailing_body_comments.
Fixes#5463