vimrc: Add CopyGitURLToLineOrRange mapping

vimrc

@@ -246,6 +246,16 @@ xmap ah <Plug>(GitGutterTextObjectOuterVisual)
 " vim-fugitive
 packadd! vim-fugitive       " https://github.com/tpope/vim-fugitive.git
 
+" Copy Git permalink to clipboard for either current line or range
+function! CopyGitURLToLineOrRange() range
+  if a:firstline == a:lastline
+    execute ".GBrowse!"
+  else
+    execute a:firstline . "," . a:lastline . "GBrowse!"
+  endif
+endfunction
+map <leader>u :call CopyGitURLToLineOrRange()<cr>
+
 " vim-go
 " Doesn't work in after/ftplugin/go.vim:
 let g:go_def_mapping_enabled = 0