[core] Fix running docs:api on Windows and other minor spelling mistakes

[joshwooding]

• I have followed (at least) the PR section of the contributing guide.

• Fixed running docs:api on Windows 🎉

• Other minor spelling mistakes

I've already made the capitalization fixes on crowdin

Closes #13972

[oliviertassinari]

@joshwooding wow, you have just made @mbrookes the happiest man. Well done! 👌

[mbrookes]

@joshwooding Awesome!

@oliviertassinari I thought we were going to wait 24 hours from review to merge? I found a correction to a correction. 😄

[oliviertassinari]

A correction to a correction 🎅

[joshwooding]

@mbrookes What was the correction?

[mbrookes]

@joshwooding

- anymore
+ any more

(https://github.com/mui-org/material-ui/pull/13989/files#diff-39e7b753e605707c8bb4540a78d52a42L125)

But honestly, in the grand scheme of things it's tiny - I can't believe how many typos, spelling mistakes and grammatical errors you managed to find!

[joshwooding]

@mbrookes Ahh okay, I guess since anymore is valid in American English I didn't fully pick up on it. I'm still confused about whether the documentation is written in American English or British English due to the amount of 'z's I normally try to write in American English. I'm sure there are more to find :P Sadly there doesn't seem to be many good tools on spell checking over this sort of stuff

[oliviertassinari]

I would lean towards American English because it has a broader audience.

[mbrookes]

anymore is valid in American English

Learned something new!

Yes, we've been using (mostly) American English (e.g. 'color'), but now doubt plenty of British / International English spellings have slipped in.