Fix PSAvoidLongLines Example

[floh96]

PR Summary

In the example the parameter was not named correct.

PR Checklist

• [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
• Make sure all .cs, .ps1 and .psm1 files have the correct copyright header
• Make sure you've added a new test if existing tests do not effectively test the code changed and/or updated documentation
• 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.

[rjmholt]

@thomasrayner if you approve, I can merge

[thomasrayner]

Looks good to me!