docs(contributing): make the good/bad pair's tense contrast unambiguous (objectui#9649)

"read" is spelled the same in the present and the past, so the pair did not
show the tense difference the rule asks for. "used" / "use" does.

Claude-Session: https://claude.ai/code/session_01EBx9rvB7dufCz4at53x35U
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

CONTRIBUTING.md

@@ -601,10 +601,10 @@ Commandment #9 of [AGENTS.md](./AGENTS.md) is the general rule.
 
 ```markdown
 ✅ Good:
-- Measured on this branch's base (`abc1234`): 14 call sites read the retired prop; all 14 are rewritten.
+- Measured on this branch's base (`abc1234`): 14 call sites used the retired prop; all 14 are rewritten.
 
 ❌ Bad:
-- 14 call sites in the repository read the retired prop.
+- 14 call sites in the repository use the retired prop.
 ```
 
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