Fix typos in user manual #4730

Job	Run time
Prepare CodeQL unit test matrix	5s
Run unit tests (c, 2.21.4, codeql-cli/v2.21.4, codeql-bundle-v2.21.4, ubuntu-latest-xl, codeql-cl...	45m 9s
Run unit tests (cpp, 2.21.4, codeql-cli/v2.21.4, codeql-bundle-v2.21.4, ubuntu-latest-xl, codeql-...	2h 27m 43s
Validate test results	6s
	3h 13m 3s

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