feat(docs): add an "Edit on GitHub" entry to the page context menu

[GigaHierz]

Split out of #2293, where it was too wide a footprint for an orphan-audit PR.

Why

The docs used to have an "Edit this page" control and it was used internally. It does not render today, and the fix you would reach for first is not available.

feedback.suggestEdit was a mint.json v1 key. Against https://mintlify.com/docs.json — which docs.json line 2 already declares as its $schema:

$ curl -sL -A 'Mozilla/5.0' https://mintlify.com/docs.json -o mint-schema.json
$ grep -oiE "feedback|suggestEdit|raiseIssue|thumbsRating" mint-schema.json | sort -u
(no output)

Zero matches for all four, and no edit key of any kind in the schema. Nothing in Mintlify's own llms.txt describes such a control, and curl on a live page finds no "Suggest edits" / "Edit this page" affordance.

What this does

Adds a custom entry to contextual.options, which surfaces in the page context menu on every page next to Copy, View and the AI tool entries already configured.

The limitation, stated plainly

The link cannot be per page. Mintlify substitutes $path only inside query-parameter values, not in the base URL, so github.com/celo-org/docs/edit/main/<path>.mdx is not expressible through this mechanism. The entry opens the repository, and GitHub's own edit → pull request flow continues from there. The description says exactly that rather than implying a deep link.

I did try to do better. A per-page link is expressible via GitHub code search:

{ "base": "https://github.com/search", "query": [{ "key": "q", "value": "repo:celo-org/docs path:$path" }] }

but GitHub code search requires authentication, so a logged-out reader gets a login wall instead of the file. That is worse than landing on the repo, so I did not use it.

If the per-page control matters, it is a Mintlify feature request — worth adding to the support thread already open under #2238.

Verification

$ python3 -c "import json; json.load(open('docs.json'))"   # parses
$ npx mintlify broken-links
success no broken links found

Shape checked against the schema's custom contextual option: title, description, icon, href, with additionalProperties: false. I left iconType off deliberately — Mintlify's prose documents it but the published schema does not list it, so including it risks failing validation.

Companion change in #2293 rewords the support section on build-on-celo/index so it no longer promises a control that does not exist. That PR stands alone; this one can land before or after it.