* Allows to use quickfix for references.
E.g. following mapping could be used to find references for item under
cursor and put result into quickfix list:
```
nnoremap <leader>af :ALEFindReferences -quickfix<CR>
```
Fixes#1759
* Documentation update.
It is easier to explain this fix with an example:
* tsserver and LSPs ask for error information when you want to fix
error. tsserver `ts@getCodeFixes` command needs tsserver error code.
* now let's imagine that user has eslint and tsserver in use. Sometimes
both can report same error in different way.
* Now there is no guarantee which error will come first and if eslint
error comes first then tsserver will not return code fixes as we are
passing wrong error code to it.
This fix will return proper error code based on linter.
Dalius Dobravolskas