chore(metadata): improve tags for common no-result searches (#5187)

* feat(metadata): improve tags for common no-result searches

Adds tags for the most frequent icon searches that returned nothing in
the last 30 days of site search data (customer, job, checklist, docs,
sell, invite, csv, budget, install, deploy, 404, ...).

Groups:
- Extend `user`, `check`, `x`, `exclamation-mark`, `question-mark`,
  `chart`, `code`, `search` and `exit` with missing synonyms.
- Add `face` group for the `face-*` icons (emoji, emotion, mood,
  feeling, expression, reaction).
- Add `dashed` group for icons drawn with a dashed outline, so
  "dotted" finds them.
- Use `$group:exit` on the diagonal `*-exit` arrows and `$group:code`
  on `terminal` and `square-terminal`.

Icons: add tags to ~100 icons for the top concept gaps, and drop
literals that a group or `$extends` now provides.

Replaying the top 3,000 no-result queries against this branch with the
site's Fuse settings: 173 queries (8,197 searches) now return results.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01G9u8Feg8TihZv9E4BxmKpt

* feat(metadata): rename `face` group to `emoticon`, tag `eye` with "eyes"

"eyes" (187 no-result searches in 30 days) did not match the eye icons:
Fuse treats the extra "s" as a typo past its threshold.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01G9u8Feg8TihZv9E4BxmKpt

---------

Co-authored-by: Claude <noreply@anthropic.com>

groups/code.json

@@ -4,6 +4,8 @@
   "tags": [
     "coding",
     "programming",
-    "development"
+    "development",
+    "developer",
+    "dev"
   ]
 }