Developer documentation fix and message fix of PossibleIncorrectUsageOfRedirectionOperatorDescription

PR Summary

A couple of minor updates to the documentation. One in rule description and the other in readme.

[X] PR has a meaningful title
- Use the present tense and imperative mood when describing your changes
[X] Summarized changes
[X] Change is not breaking
[X] Make sure all .cs, .ps1 and .psm1 files have the correct copyright header
[X] Make sure you've added a new test if existing tests do not effectively test the code changed and/or updated documentation
[X] This PR is ready to merge and is not Work in Progress.
- If the PR is work in progress, please add the prefix WIP: to the beginning of the title and remove the prefix when the PR is ready.