docs: clarify path matching behavior for route methods vs app.use() (#1941)

[kushal4345]

This PR updates the documentation to address #1941 issue

Adds a note explaining that:

app.use() uses prefix-based path matching (e.g., /api will match /api/users).
HTTP method handlers (app.get(), app.post(), etc.) use exact path matching (e.g., app.get('/api') will only match /api).
Provides a clear code example to highlight the difference.
Ensures users are not confused when switching between app.use() and route methods.

This improves the clarity of the path examples section in the docs.

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🚦 Lighthouse Results (Mobile & Desktop)

URL	Device	Perf	A11y	Best Practices
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/en/blog/posts.html	mobile	🔴 71	🟢 96	🟢 93
/en/5x/api.html	mobile	🔴 63	🟢 95	🟢 96
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/en/blog/posts.html	desktop	🟢 92	🟢 96	🟢 93
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