Check for broken links about documentation

[paf31]

Using https://www.npmjs.com/package/markdown-link-check gives the complete list:

$ find . -name '*.md' | cut -c 3- | xargs -L 1 markdown-link-check | grep ✖

[✖] https://github.com/purescript/purescript/tree/master/psc-ide-server
[✖] https//pursuit.purescript.org/
[✖] https://github.com/purescript/purescript/tree/master/psc-ide-server
[✖] http://purescript.readthedocs.org
[✖] http://tryps.functorial.com
[✖] https://github.com/purescript/purescript-promises
[✖] http://purescript.readthedocs.org/en/latest/prelude.html
[✖] http://functorial.com/purescript
[✖] language/Related-Projects.md

[grdryn]

I happened to come across a couple of broken links here, so putting a PR together. I'll see if there are any others so that maybe my PR can satisfy this issue.

[hdgarrood]

Any PRs fixing broken links would be very welcome :) I wouldn't put effort in writing a script to check just yet, though, as I would like to switch over to Sphinx at some point, which will do this for us.

[grdryn]

@hdgarrood #7 fixes almost all of the broken links.

There are some in Pre-0.5-changelog.md that I didn't bother trying to find working links for.

There's also one link broken under History in Wikipedia-Page-Proposal.md. The relevant part there is:

Historical note: first SlamData PS commit on May 9, 2014 (https://github.com/slamdata/slamdata-nodewebkit/commit/73e3c9d5710ebf21552699e6bbe87f412171aec8)

and the slamdata/slamdata-nodewebkit at least doesn't seem to be a publicly accessible repo any longer.

[grdryn]

I wouldn't put effort in writing a script to check just yet, though, as I would like to switch over to Sphinx at some point, which will do this for us.

@hdgarrood ah, that's what you meant by "Check for broken links"? I guess #7 fixes this for a single point in time only then. :)

[subttle]

Currently a broken link for "psc-ide" here:
https://github.com/purescript/documentation/blob/master/ecosystem/Editor-and-tool-support.md

It was suggested on IRC that the link should now point to:
https://github.com/purescript/documentation/blob/master/guides/psc-ide-FAQ.md