Fix typos in user manual #4724

Job	Run time
Prepare CodeQL unit test matrix	7s
Run unit tests (c, 2.21.4, codeql-cli/v2.21.4, codeql-bundle-v2.21.4, ubuntu-latest-xl, codeql-cl...	46m 34s
Run unit tests (cpp, 2.21.4, codeql-cli/v2.21.4, codeql-bundle-v2.21.4, ubuntu-latest-xl, codeql-...	2h 17m 55s
Validate test results	3s
	3h 4m 39s

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