De-dupe autocomplete results

Duplicates appear when overriding a default command via a projection

Author: Mike Foley

autoload/rails.vim

@@ -2537,7 +2537,7 @@ function! s:completion_filter(results, A, ...) abort
   if exists('*projectionist#completion_filter')
     return projectionist#completion_filter(a:results, a:A, a:0 ? a:1 : '/')
   endif
-  let results = sort(type(a:results) == type("") ? split(a:results,"\n") : copy(a:results))
+  let results = uniq(sort(type(a:results) == type("") ? split(a:results,"\n") : copy(a:results)))
   call filter(results,'v:val !~# "\\~$"')
   if a:A =~# '\*'
     let regex = s:gsub(a:A,'\*','.*')