docs: fix grammar errors in README, examples, and integration test comments

[strbrgr]

While reading through the docs and source comments I noticed a handful of typos/grammar
errors. Listing them here to get approval before sending separate PRs (or one PR
per file if preferred).

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README.md:236

"Iggy requires credentials to authenticate request to the server."

request → requests

---

examples/rust/src/message-headers/message-compression/README.md

Multiple issues in this file:

• Line 44: to be send to the server → to be sent to the server
• Line 58: A message send to the server → A message sent to the server
• Line 74: sends it's application logs → sends its application logs
• Line 78: by trading of some idle CPU time → by trading off some idle CPU time
• Line 84: tells us, that → tells us that / thats → that's

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core/integration/tests/server/scenarios/stream_size_validation_scenario.rs

• Line 107: it's message count → its message count
• Line 127: it's topics → its topics

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core/integration/tests/server/scenarios/log_rotation_scenario.rs:259

"So there ignores tiny minor overflow"

there → this

---

Happy to split into separate PRs per file if that's cleaner. Let me know how you'd like these handled.

[spetz]

Hey,
Please feel free to create a single PR with all improvements if possible.

Also, there's another repository apache/iggy-website which hosts our iggy.apache.org website along with all the docs that might need some additional type checking too :)