Avoid unnecessary copy of completion candidates

Author: krobelus

src/input_handler.cc

@@ -1085,7 +1085,7 @@ class Prompt : public InputMode
                     items.push_back({ candidate, {} });
 
                 const auto menu_style = (m_flags & PromptFlags::Search) ? MenuStyle::Search : MenuStyle::Prompt;
-                context().client().menu_show(items, {}, menu_style);
+                context().client().menu_show(std::move(items), {}, menu_style);
 
                 if (menu)
                     context().client().menu_select(0);