style(skills): clear the markdownlint findings that kept make test red

Eight findings, none of them in a skill written recently, all of them loud enough to hide the next real one. merge-fix opened two code fences without a language, and no-defaults wrote its table separator as |---|---|---| while all six data rows put spaces around the pipes, which markdownlint reads as a style contradiction and reports six times over for that single line.

Nothing about the rendered documents changes: the fence language only selects highlighting, and the separator row is not rendered at all. make test now passes end to end, so the next finding it reports will be a new one.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

skills/merge-fix/SKILL.md

@@ -20,7 +20,7 @@ same tree may own.
 
 ## 2. Fetch everything
 
-```
+```bash
 git fetch --all --prune --tags
 ```
 
@@ -37,7 +37,7 @@ one line so a wrong reading is visible before the search.
 
 Run all three; they find different things:
 
-```
+```bash
 git log --all --oneline --regexp-ignore-case --grep='<keyword>'
 git log --all --oneline -S'<symbol or literal>'
 git log --all --oneline -- '<path or glob>'