* 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>
564dd7d8db
