Commit transient edit when closing pager

When selecting items in the pager, only the latest of those items is kept
in the edit history, as so-called transient edit.  Each new transient edit
evicts any old transient edit (via undo).

If the pager is closed by a command that performs another transient edit
(like history-token-search-backward) we thus inadvertently undo (= remove)
the token inserted by the pager.  Fix this by closing a transient edit
session when closing the pager.  Token search will start its own session.

Fixes #9160

src/reader.cpp

@@ -2045,6 +2045,7 @@ void reader_data_t::accept_autosuggestion(bool full, bool single, move_word_styl
 void reader_data_t::clear_pager() {
     pager.clear();
     history_pager_active = false;
+    command_line_has_transient_edit = false;
 }
 
 void reader_data_t::select_completion_in_direction(selection_motion_t dir,