reader: repaint commands to not disable "last_cmd"-based UI states (pager etc.)

"commandline -f repaint" might be triggered for various reasons;
since this sets "last_cmd", it will reset some UI states, notably
pager selection:

1. press tab
2. trigger repaint
3. press tab

The repaint prevents us from selecting the first candidate.

Work around this by ignoring repaint events for the last_cmd logic.

Fixes #12683

src/reader/reader.rs

@@ -1154,9 +1154,9 @@ pub fn reader_execute_readline_cmd(parser: &Parser, ch: CharEvent) {
     if matches!(
         readline_cmd_evt.cmd,
         ReadlineCmd::ClearScreenAndRepaint
+            | ReadlineCmd::ForceRepaint
             | ReadlineCmd::RepaintMode
             | ReadlineCmd::Repaint
-            | ReadlineCmd::ForceRepaint
     ) {
         data.queued_repaint = true;
     }
@@ -2847,7 +2847,9 @@ fn handle_char_event(&mut self, injected_event: Option<CharEvent>) -> ControlFlo
                     self.command_line_transient_edit = None;
                 }
 
-                self.rls_mut().last_cmd = Some(readline_cmd);
+                if !command_only_affects_rendering(readline_cmd) {
+                    self.rls_mut().last_cmd = Some(readline_cmd);
+                }
             }
             CharEvent::Command(command) => {
                 self.run_input_command_scripts(&command);
@@ -6291,6 +6293,15 @@ fn command_ends_history_search(c: ReadlineCmd) -> bool {
     )
 }
 
+fn command_only_affects_rendering(c: ReadlineCmd) -> bool {
+    #[allow(non_camel_case_types)]
+    type rl = ReadlineCmd;
+    matches!(
+        c,
+        rl::ClearScreenAndRepaint | rl::ForceRepaint | rl::RepaintMode | rl::Repaint
+    )
+}
+
 /// Return true if we believe ourselves to be orphaned. loop_count is how many times we've tried to
 /// stop ourselves via SIGGTIN.
 fn check_for_orphaned_process(loop_count: usize, shell_pgid: libc::pid_t) -> bool {