What does this PR do

This PR fixes some errors found by our checker:

$ ./topgrade_i18n_locale_file_checker --locale-file ../topgrade/locales/app.yml --rust-src-to-check ../topgrade/src
Errors Found:
  UseOfKeysDoNotExist
    file '../topgrade/src/self_update.rs' / line '52' / column '27' / key 'Respawning...'
    file '../topgrade/src/steps/os/windows.rs' / line '202' / column '21' / key 'Could not find Topgrade in any WSL disribution'
    file '../topgrade/src/steps/os/windows.rs' / line '209' / column '20' / key 'Windows Update'
    file '../topgrade/src/main.rs' / line '488' / column '19' / key '\n(R)eboot\n(S)hell\n(Q)uit'

For the first 3 errors, they are keys that have not been added to our locale file. The last one is interesting, we already have it in the locale file:

"\n(R)eboot\n(S)hell\n(Q)uit":
  en: "\n(R)eboot\n(S)hell\n(Q)uit"

But it was enclosed with double quotes, which treated the \n as a new line rather than a string literal, using single quotes fixes the issue.

Standards checklist

• The PR title is descriptive.
• I have read CONTRIBUTING.md
• Optional: I have tested the code myself

For new steps

• Optional: Topgrade skips this step where needed
• Optional: The --dry-run option works with this step
• Optional: The --yes option works with this step if it is supported by
  the underlying command

If you developed a feature or a bug fix for someone else and you do not have the
means to test it, please tag this person here.