Update the jumplist when jumping between references

The previous jump method (using G) set a jump, but cursor() doesn't, so
we manually update the jumplist before moving the cursor so as to not
take away previously existing functionality (the ability to use <C-O> to
undo a jump)

Author: Daniel Hakimian

autoload/lsp/ui/vim/references.vim

@@ -221,5 +221,6 @@ function! lsp#ui#vim#references#jump(offset) abort
 
     " Jump
     let l:target = w:lsp_reference_positions[l:index][0:1]
+    normal! m`
     call cursor(l:target[0], l:target[1])
 endfunction