Fix Spelling Errors (backport #152)

[mergify]

🦟 Bug fix

Fixes #151

Summary

Fixes various spelling mistakes.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

---

This is an automatic backport of pull request #152 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 705c038 has failed:

On branch mergify/bp/ign-tools1/pr-152
Your branch is up to date with 'origin/ign-tools1'.

You are currently cherry-picking commit 705c038.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   Migration.md
	modified:   cmake/run_test.cmake
	modified:   etc/ign.bash_completion.sh
	modified:   src/Backward/README.md
	modified:   src/Backward/backward.hpp

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   Changelog.md

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[j-rivero]

@osrf-jenkins run tests