Create frequently-asked-questions-about-fsrs.md

[Expertium]

I want to transfer this section of the GitHub guide here: https://github.com/open-spaced-repetition/fsrs4anki/blob/main/docs/tutorial.md#faq

It has a lot of questions, so I did my best to select the ones I consider to be especially important and/or frequently asked.

[Expertium]

@brishtibheja @L-M-Sherlock feedback is welcome

[Expertium]

@dae this PR has been (almost) ready for a few days now, would be nice if you answered one last question - should we keep the question-answer pair about availability of FSRS on different platforms - and merged it.
Also this ankitects/anki-manual#264

[dae]

should we keep the question-answer pair about availability of FSRS on different platforms

I'm sorry, I'm not sure what you're asking me there. The PR otherwise looks ok.

[Expertium]

@dae I meant this

Q1: Which platforms support FSRS?

A1: FSRS is supported on all platforms: desktop Anki (Windows, Mac, and Linux), AnkiWeb (browser), AnkiMobile (iOS), and AnkiDroid (Android). Make sure that your Anki(Mobile) version is 23.10 or newer, and your AnkiDroid version is 2.17 or newer.

Based on your other comment, I'll remove it.

[dae]

By the way, I recall talk of content in the FAQs page vs the manual, but not sure where I saw it. Recently, I've come to feel that a FAQ page is more a convenience for support people, and the info is better placed in the manual instead. In the future, I'd like to see us improving the manual, and removing the entries of the FAQ page.

[Expertium]

I don't understand why the manual and FAQ have different Github repositories in the first place