fix: restore fallback mechanism when jumping by property

Author: soifou

lua/blink/cmp/completion/list.lua

@@ -213,7 +213,7 @@ function list.select_next(opts)
     return list.select(1, opts)
   end
 
-  if opts and opts.jump_by then return list.jump_by(1, opts) end
+  if opts and opts.jump_by and list.jump_by(1, opts) then return true end
 
   -- fallback, select the next item
   local count = opts and opts.count or 1
@@ -243,7 +243,7 @@ function list.select_prev(opts)
     return list.select(#list.items, opts)
   end
 
-  if opts and opts.jump_by then return list.jump_by(-1, opts) end
+  if opts and opts.jump_by and list.jump_by(-1, opts) then return true end
 
   -- fallback, select the previous item
   local count = opts and opts.count or 1