Use link targets that resolve for the aggregation cross-references

[GuanzhouSong]

Summary

Seventeen cross-reference links across six pages point at relative .md paths, and every one of them 404s.

On $search, the link to $vectorSearch renders as:

href="./%24vectorsearch.md"

documentdb.io serves these pages with a trailing slash, so that resolves against the page's own directory and lands at /operators/aggregation/$search/%24vectorsearch.md — wrong depth and a leaked extension, the two failure modes #57 catalogued, in a single href. Confirmed 404 against the live site.

Affected

File	Links
$search.md	5
$project.md	4
$vectorsearch.md	3
$graphlookup.md	2
$limit.md	2
$meta.md	1

They were introduced together: $vectorSearch, $project, $limit and $graphLookup arrived in #59, $search in #64 following the convention it found on the page beside it, and $meta links back the same way. None of them render, so those pages read as cross-linked while every cross-link is dead.

Fix

Rewritten to the absolute form the rest of the reference already uses:

https://documentdb.io/docs/reference/operators/aggregation/%24bucket/

That is what #57 settled on for exactly this reason — it does not depend on how the site resolves a relative path, and it survives a page moving between directories.

Verification

All 13 distinct targets were requested against the live site and return 200. No relative .md link remains anywhere in the repository:

$ grep -rn '](\.\{1,2\}/[^)]*\.md)' --include="*.md" . | wc -l
0

Related: this is the class of #38, which stays open for the wider .md-in-links question.

[guanzhousongmicrosoft]

Confirmed against the live site: the relative form 404s, all 13 absolute targets return 200, and no relative .md link remains in the repo.