Review forks and pick up any generally useful fixes or features

[alerque]

For context on why I'm bringing this up, please see #549.

As is to be expected for OSS projects, during the years that issues and PRs were going without much motion or feedback, several forks cropped up. Many of them don't have anything at all, most only have one or two little fixes to scratch an itch of their own, but a few even have extensive sets of fixes and features. As far as I know poking through the network graph is the most useful place to find changes. We should scour through them to see what, if anything, is generally useful and could be contributed back here.

This issue is to note things that should probably be pursued and track progress on including them, which might take a while.

• @ezequielv's fork has 15 commits.

• @gasparch's fork has 20 commits, most of which seem to me merges so it's not readily apparent if anything is new. Possibly this comment explains what's going on there.

• ...

[heroin-moose]

Also consider https://github.com/liuchengxu/vista.vim. It's buggy as hell, but pairing with LSP and poup preview window are both very nice features.

[alerque]

@heroin-moose That is not exactly in scope for this issue and should be tracked separately. This is specifically about the mess created in forks of this plugin during the time it was unmaintained. Looking into features from other competing plugins is a different kettle of fish. Vista.vim does have some nice things (I've toyed with replacing my use of tagbar with it several times), but I would suggest opening up separate feature request issues for each thing you really like. That will make it much easier to discuss and track progress.

Also a reminder that PRs are welcome. I probably won't be putting a lot of development time into new features on this, just maintaining what is here and keeping the project alive and tidy. I'm happy to help coordinate and integrate contributions, but progress on new features is going to depend on community involvement.