fix(autofmt): preserve indentation of commented-out RSX blocks (#5464)

* 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

packages/autofmt/tests/samples.rs

@@ -69,6 +69,11 @@ twoway![
     blank_lines,
     blank_lines_preserved,
     forloop_tuple,
+    commented_rsx_block,
+    commented_rsx_block_nested,
+    commented_rsx_block_only,
+    commented_rsx_block_between,
+    commented_rsx_block_deep,
 ];
 
 fn assert_idempotent(src: &str) {