Insert parentheses to function completion and equals to arg completion

[renkun-ken]

Closes #167.

This PR:

• Insert () after function name when function completion item is selected
• Insert = after argument name when arg completion item is selected.

[randy3k]

Thank you.

[krassowski]

Am I right that snippets should be only returned if the client declared snippetSupport? I think that we are sending snippetSupport=false but getting the snippets anyway.

Not that I do not want to implement this (it is great to see new features added!), just checking what is you opinion here.

[randy3k]

@krassowski you are absolutely correct.

[marskar]

This only works for snippets, correct?
Is there anyway to autocomplete parentheses for all functions with snippets?
The Python LSP has a setting that can be enabled.

[renkun-ken]

@marskar Inserting fun($0) while seeing fun in completion list is only supported by editor that has snippetSupport capability. Seems it has nothing to do with user snippets. If editor has snippetSupport, then all functions will insert parentheses automatically.

[marskar]

@renkun-ken, thanks, autocompleting parentheses works well great for me now.
If anyone reads this and is curious about the setup,
I

• brew installed node
• vim-plug installed coc.vim
• ran install.packages("languageserver")
• added the code below to the .Rprofile in my home directory:

options(
    languageserver.server_capabilities = list(
        snippetSupport = TRUE
    )
)

[randy3k]

By the way, I don't think

options(
    languageserver.server_capabilities = list(
        snippetSupport = TRUE
    )
)

is valid. snippetSupport is a behavior supported by the editor or editor plugins. In your case, it seems that coc.vim already supports snippetSupport.