fim: restore trailing empty line removal on split

The old s:fim_render() stripped trailing empty strings from the split
content lines. This was lost in the refactor, causing extra empty lines
on accept and incorrect cursor positioning (cursor at column 1 of an
empty trailing line instead of the last meaningful line).

Assisted-by: llama.cpp:local pi

Author: ggerganov

autoload/llama.vim

@@ -1080,7 +1080,12 @@ function! s:fim_try_hint(pos_x, pos_y)
             if l:fuzzy_offset >= 0 && len(l:content) > l:fuzzy_offset
                 let l:content = l:content[l:fuzzy_offset + 1:]
             endif
-            call add(l:completions, split(l:content, "\n", 1))
+            let l:lines = split(l:content, "\n", 1)
+            " remove trailing empty lines
+            while len(l:lines) > 0 && l:lines[-1] == ""
+                call remove(l:lines, -1)
+            endwhile
+            call add(l:completions, l:lines)
         endfor
 
         " store fuzzy info so cycling applies the same trimming