Save the screen status after running command bindings

This concerns running a key binding which invokes a command. If that
command modifies the tty, then fish will spot the modification later and
then react to it by redrawing the prompt. However tty modifications may
be benign or desirable; for example switching the cursor from a line to
a block. Fix this by re-fstating the tty after running external
commands.

Fixes #3481

CHANGELOG.rst

@@ -89,6 +89,7 @@ Interactive improvements
 - ``time`` now emits an error if used after the first command in a pipeline (:issue:`8841`).
 - ``fish_add_path`` now prints a message for skipped non-existent paths when using the ``-v`` flag.
 - Since fish 3.2.0, pressing :kbd:`Control-D` while a command is running would end up inserting a space into the next commandline, which has been fixed (:issue:`8871`).
+- A bug that caused multi-line prompts to be moved down a line when switching between insert and normal mode has been fixed (:issue:`3481`).
 
 New or improved bindings
 ^^^^^^^^^^^^^^^^^^^^^^^^

src/reader.cpp

@@ -3079,6 +3079,10 @@ void reader_data_t::run_input_command_scripts(const wcstring_list_t &cmds) {
         wperror(L"tcsetattr");
     }
     termsize_container_t::shared().invalidate_tty();
+
+    // The input command scripts may have changed our tty - ignore any such changes.
+    // See #3481.
+    screen.save_status();
 }
 
 /// Read normal characters, inserting them into the command line.