fix(lsp): ignore empty response on trigger completion #37663

Problem:
Empty response affects server start boundary computed before.

Solution:
Ignore empty responses. This is mostly micro-optimization that avoids
extending existing results with empty responses.

runtime/lua/vim/lsp/completion.lua

@@ -583,7 +583,7 @@ local function trigger(bufnr, clients, ctx)
       end
 
       local result = response.result
-      if result then
+      if result and #result.items > 0 then
         Context.isIncomplete = Context.isIncomplete or result.isIncomplete
         local encoding = client and client.offset_encoding or 'utf-16'
         local client_matches, tmp_server_start_boundary