fix: parse block quote markers of table lines as BLOCK_QUOTE tokens (IJPL-95908)

[jetbrains-air]

Fixes IJPL-95908: removing a row / column in a table inside a block quote breaks the table.

Root cause

For a table inside a block quote, only the first > marker got a BLOCK_QUOTE token production (via populateConstraintsTokens). The > markers of the separator line and of every data row fell into the gaps between block-level productions, and TreeBuilder/TopLevelBuilder.addRawTokens fills such gaps with WHITE_SPACE tokens.

In the IDE those markers therefore ended up inside PsiWhiteSpace nodes (MarkdownParserDefinition.getWhitespaceTokens() includes the library WHITE_SPACE). The table actions themselves don't touch the prefixes — but the whitespace regeneration that the platform performs after a PSI mutation can only emit real whitespace, so the > markers were silently dropped, breaking the block quote markup and the table with it. A plain table survives the same mutation, which is why the bug shows only inside a block quote.

Fix

GitHubTableMarkerBlock now emits a BLOCK_QUOTE token production for each quote marker (plus one following space, when eaten by the constraints) on every table continuation line, matching how the markers are represented outside of tables:

Markdown:EOL('\n')
WHITE_SPACE('   ')
Markdown:BLOCK_QUOTE('> ')
Markdown:ROW

previously:

Markdown:EOL('\n')
WHITE_SPACE('   > ')
Markdown:ROW

Pure indentation (tables in list items) intentionally stays WHITE_SPACE.

Testing

• New testTableInsideBlockQuote parsing test covering the exact reproducer from the issue (>| without a space) and a nested >>| block quote.
• Updated expected trees of testTableInsideBlockQuoteWithMissingLastPipe and testTableInsideBlockQuoteInListItem — only the token type of the > prefixes changed.
• Full jvmTest suite passes (1566 tests), including the GFM spec suite: HTML generation is unaffected because TablesGeneratingProvider only consumes HEADER/ROW/TABLE_SEPARATOR children.

Produced by Air Automations. Name: Markdown library: fix the bug / Run: https://air.jetbrains.cloud/org/05cf1a7f-6ab5-713b-abd3-29d0c8a05e2d/automations/cb6a17f6-e7a9-41a8-9611-7c95c4eb0141?run=e31aa195-850b-47a7-8b0b-bc40ea2ca4a5

🤖 Generated with Claude Code

[Ilia Permiashkin (p3rmiashkin)]

Seems to be duplicated of #231 :( Peter Gromov (@donnerpeter) WDYT?

[jetbrains-air]

Approving verdict from my side — no blocking findings! (Posted as a comment because GitHub does not allow this account to formally approve its own PR.)

Produced by Air Automations. Name: Markdown library: review the PR / Run: https://air.jetbrains.cloud/org/05cf1a7f-6ab5-713b-abd3-29d0c8a05e2d/automations/2269eaa4-da15-4cac-957f-3341151c79ec?run=c915e52e-62ca-4c77-9351-57b81d857d7c