Web: use the word "Web" correctly and consistently

[daxpedda]

Removing any public mentions of web-sys, because its currently the only backend we support anyway, so this is a historical leftover when we were still supporting stdweb.

About the casing of "Web", apparently OED (Oxford English Dictionary) says its capital unless used in a compound word, e.g. "I am surfing the Web." vs "I am a web user.". Unfortunately I can't link to the OED because its behind a paywall. I didn't want to spend time actually figuring out what exactly are compound words or aren't, so I just opted to use capital casing everywhere.

[kchibisov]

The WebSys should go away from the docs as well?

Also, it's not clear why docsrs was added.

[daxpedda]

The WebSys should go away from the docs as well?

CI was failing because of that, fixed it now.

Also, it's not clear why docsrs was added.

Because when cfg(docsrs) is enabled it can be linked, that's the whole purpose of this cfg, to avoid linking to it when its not present.

[kchibisov]

But it'll fail when building for docsrs because Web is not present? Like I don't see what was wrong with the old cfg check without docsrs.

[daxpedda]

But it'll fail when building for docsrs because Web is not present?

But Web is present for docsrs?
See #3076 if you don't remember.
Or if you have a way to reproduce a error/warning please share it.

Like I don't see what was wrong with the old cfg check without docsrs.

This is just an improvement.

[kchibisov]

Ah, forgot that we check docsrs, should be good.