docs: document the variable-substitution templating language

[kozlek]

Document each templated field's variable set as a named data type in
data-types.mdx (Message template, Copy title template, Copy body template,
Workflow input template), each rendering its variables from the JSON schema via a
new TemplateVariablesTable component that reads the x-mergify-template-variables
annotation. The simple-template field type in each action's Parameters table shows
its data-type title and links to it (getValueType: title->anchor, plus 'map of'
for the github_actions inputs map), so feature pages reference the variable set
rather than replicating a table. Adds a Variable substitution concept section with
a Jinja2 migration cheat-sheet, and re-scopes the legacy Jinja2 Template section to
the fields that still use it (post_check, merge).

[mergify]

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[Copilot]

Pull request overview

This PR documents Mergify’s new variable-substitution templating behavior in the docs and introduces a TemplateVariablesTable React component to render each templated field’s allowed variables directly from the configuration JSON schema.

Changes:

• Adds a “Variable substitution” concept section to /configuration/data-types, including limitations and a short Jinja2 migration mapping.
• Updates several workflow action pages to reference variable substitution and to render an “Available variables” table per field.
• Adds schema-driven variable extraction/rendering utilities, and adjusts options-table rendering to avoid duplicating “Allowed variables” text.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 13 comments.

Show a summary per file

File	Description
src/util/templateVariables.ts	Adds recursive extraction of x-mergify-template-variables from JSON Schema fragments.
src/util/templateVariables.test.ts	Adds Vitest coverage for the extractor across common schema shapes.
src/components/Tables/TemplateVariablesTable.tsx	New table component to render published variables for a schema field.
src/components/Tables/OptionsTable.tsx	Strips duplicated “Allowed variables” text for simple-template descriptions (now expected to be shown via the variables table).
src/components/Tables/ConfigOptions.tsx	Links simple-template value types to the new docs concept section.
src/content/docs/configuration/data-types.mdx	Adds “Variable substitution” section and clarifies that Jinja2 remains only for specific fields.
src/content/docs/workflow/actions/comment.mdx	Adds “Available variables” section and Jinja2 deprecation note for message.
src/content/docs/workflow/actions/review.mdx	Adds “Available variables” section and Jinja2 deprecation note for message.
src/content/docs/workflow/actions/close.mdx	Adds “Available variables” section and Jinja2 deprecation note for message.
src/content/docs/workflow/actions/copy.mdx	Updates templating guidance and adds variable table + deprecation note for title/body.
src/content/docs/workflow/actions/backport.mdx	Updates templating guidance and examples; adds variable table + deprecation note for title/body.
src/content/docs/workflow/actions/github_actions.mdx	Adds variable table + deprecation note for templated workflow inputs.

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[kozlek]

Revision history

#	Type	Changes	Reason	Date
1	initial	9d6355c		2026-06-23 16:10 UTC
2	content	9d6355c → 82d1dc7 (raw)		2026-06-23 16:10 UTC
3	content	82d1dc7 → 01457dd (raw)		2026-06-24 07:36 UTC
4	content	01457dd → 0e1688c (raw)		2026-06-24 10:00 UTC
5	content	0e1688c → 428c7da (raw)		2026-06-24 12:57 UTC
6	rebase	428c7da → 2128558 (rebase only)		2026-06-24 13:20 UTC

[kozlek]

This pull request is part of a Mergify stack:

#	Pull Request	Link
1	docs: document the variable-substitution templating language	#11913	👈
2	docs: clarify assignees and bot_account accept a login or the author shortcut	#11926

[mergify]

Queued — the merge queue status continues in this comment ↓.

[mergify]

Merge Queue Status

• ✅ Entered queue — 2026-06-24 15:24 UTC · Rule: default · triggered by merge protections
• ✅ Checks passed · on draft merge queue: queuing main (0f8c8de) and #11913 together #11928
• ✅ Merged — 2026-06-24 15:26 UTC · at 2128558579d992da917760634b29e621e1ecea68 · squash

This pull request spent 2 minutes 38 seconds in the queue, including 1 minute 59 seconds running CI.

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