lsp: get_language_id (#14092)

* Allow specifying a languageId for a lsp

For some languages the filetype might not match the languageId the
language server accepts. In these cases the config for the language
server can contain a function which gets the current buffer and filetype
and returns a languageId. When it isn't provided the filetype is used
instead.

Example:
```lua
require'lspconfig'.sourcekit.setup{
    get_language_id = function(bufnr, ft)
        return 'swift'
    end;
}
```

Closes #13093

* lsp: Change to get_language_id

Co-authored-by: Jan Dammshäuser <mail@jandamm.de>

0 files changed, 0 insertions, 0 deletions