Fix grammar, style, and formatting in Approximate Matching doc

[its-dave]

What does this PR aim to accomplish?:

Tidy the wording and syntax in docs/regex/approximate.md as some of it didn't make sense or was inconsistent

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[rdwebdesign]

I'd like to know @DL6ER opinion here, because he is the original author of this page.

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[github-actions]

Conflicts have been resolved.

[its-dave]

@rdwebdesign @DL6ER happy with my changes?

[yubiuser]

One formal change: please squash down all your commits

[DL6ER]

I have not even seen the first @-ping. I am not a native speaker and everybody is happily invited to improve my texts in any helpful way!

[its-dave]

@yubiuser I don't think I can squash from the UI, are you able to squash when merging?

[rdwebdesign]

I don't see any issues, but I'm also not a native speaker. Maybe @PromoFaux can check the text to make sure.

[PromoFaux]

Looks good to me

[PromoFaux]

And yes, we can do a squash merge - no worries there

[its-dave]

Thanks, and thanks all for all your work on this project!

Changes have been addressed and/or resolved