[docs] update OAuth guide in README.rst

[ClosedPort22]

No description provided.

[mikf]

One could argue that it is not entirely optional for Mastodon instances, since it is required to map user name to ID, but I have no idea how to accurately describe that here without being too verbose.

.../users/username requires an access token
.../users/id:12345 works without
(for instances that are not supported by default)

[ClosedPort22]

I think the current description is okay, since it's not entirely non-functional without the token, unlike Pixiv. Maybe a more detailed description could be added to configuration.rst (although extractor.mastodon.access-token is currently undocumented).

[ClosedPort22]

And by the way, I think the dot in mastodon.social is messing up -o. extractor.mastodon.social.access-token=foo doesn't work.

[rautamiekka]

extractor.mastodon.social.access-token=foo.

It's never been used like that anyway.

[ClosedPort22]

extractor.mastodon.social.access-token=foo.

It's never been used like that anyway.

I do use this feature from time to time. Both extractor.pawoo.access-token=foo and extractor.mastodon.access-token=foo (all instances) work fine.

[rautamiekka]

I mean it's never used with the TLD.

[ClosedPort22]

I mean it's never used with the TLD.

That's the identifier used by the instance:

gallery-dl/gallery_dl/extractor/mastodon.py

Lines 72 to 73 in a918ce2

	INSTANCES = {
	"mastodon.social": {

I think it would work just fine in the config file, which doesn't use dot notation, but perhaps something like an underscore would've been a better choice.

[rautamiekka]

Ok, fair enough.

[mikf]

Yeah, it was a bad decision to use mastodon.social with a dot as category name, but I'd rather not change it right now (backwards compatibility and such).

I think it would be best to eventually (v2.0?) change the dot notation for -o to use a different character altogether, maybe -o mastodon.social:access-token=TOKEN.