Recommend LanguageClient-neovim instead of vim-solargraph

[guilleiguaran]

LanguageClient-neovim seems better supported, per vim-solargraph README:

Please consider this as a first prototype pre ALPHA version, just to prove that it can be done

I've created an PR to add an example about how to configure it with Solargraph: autozimu/LanguageClient-neovim#799

Note also that there are some outstanding issues in vim-solargraph like the lack of support of recent versions of solargraph and Language Server

Note: Despite of the neovim suffix in the name of the library it supports vim as well.

[guilleiguaran]

autozimu/LanguageClient-neovim#799 has been merged so users of LanguageClient will have an idea about how to use it with Solargraph 😊

[castwide]

Thanks, @guilleiguaran. Looks good to me.