Fix crash in formatter on comment lookalikes in JSX closing tags

[Mateusz Burzyński (Andarist)]

fixes the issue reported here: #64622 (comment)

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Review effort: Lite
Findings: 1 · 1 · 1

Open (3)

• In the actionRescanLessThanSlashToken case, when token != ast.KindLessThanToken the branch… · New
• The PR title/description focuses on the JSX closing-tag comment-lookalike crash, but this PR also… · New
• Parameter name container is inconsistent with nearby helpers like… · New

What changed in this PR

Adds regression coverage and scanner logic changes to prevent formatter crashes when JSX closing tags contain comment-lookalike sequences (e.g., </* */>), matching the linked TypeScript issue.

Changes:

• Add fourslash regression tests covering JSX closing-tag /* */ lookalikes and a couple of additional formatter edge cases.
• Extend the formatting scanner with a new rescan action for JSX closing tags to avoid mis-tokenizing </ sequences.

File	Description
tsc/​internal/​fourslash/​tests/​formatTypeArgumentStartingWithLessThan_test.go	New regression test for formatting with << type-argument edge case.
tsc/​internal/​fourslash/​tests/​formatNestedJSDocNullableType_test.go	New regression test for nested JSDoc nullable type formatting.
tsc/​internal/​fourslash/​tests/​formatJsxClosingTagFollowedByAsterisk_test.go	New regression test for </* */> in JSX fragments.
tsc/​internal/​fourslash/​tests/​formatJsxClosingTagFollowedByAsteriskAfterText_test.go	New regression test for </* */a> after text in JSX.
tsc/​internal/​fourslash/​tests/​formatJsxClosingTagFollowedByAsteriskAfterExpression_test.go	New regression test for </* */a> after an expression in JSX.
tsc/​internal/​format/​scanner.go	Add a targeted rescan path for JSX closing tags to avoid interpreting /* as a comment.

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