Add a default mapping for searching the scrollback

Opens the scrollback pager in search mode. Particularly useful for
newbies on macOS that are used to using cmd+f to trigger search mode.

If there is a current selection, it is automatically searched for.

kitty/window.py

@@ -2101,11 +2101,29 @@ class Window:
     # actions {{{
 
     @ac('cp', 'Show scrollback in a pager like less')
-    def show_scrollback(self) -> None:
+    def show_scrollback(self) -> Optional['Window']:
         text = self.as_text(as_ansi=True, add_history=True, add_wrap_markers=True)
         data = self.pipe_data(text, has_wrap_markers=True)
         cursor_on_screen = self.screen.scrolled_by < self.screen.lines - self.screen.cursor.y
-        get_boss().display_scrollback(self, data['text'], data['input_line_number'], report_cursor=cursor_on_screen)
+        return get_boss().display_scrollback(self, data['text'], data['input_line_number'], report_cursor=cursor_on_screen)
+
+    @ac('cp', '''
+        Search scrollback in a pager like less. If there is selected text, it is automatically searched for.
+        Note that this assumes that pressing the / key triggers search mode in the page configured as the
+        scrollback pager.
+    ''')
+    def search_scrollback(self) -> None:
+        text = self.text_for_selection()
+        w = self.show_scrollback()
+        if w is not None:
+            w.send_key('/')
+            if text:
+                btext = text.encode()
+                sanitized = replace_c0_codes_except_nl_space_tab(btext)
+                if not w.screen.in_bracketed_paste_mode:
+                    sanitized = sanitized.replace(b'\n', b'\x1bE')
+                w.screen.paste_bytes(sanitized)
+                w.send_key('enter')
 
     def show_cmd_output(self, which: CommandOutput, title: str = 'Command output', as_ansi: bool = True, add_wrap_markers: bool = True) -> None:
         text = self.cmd_output(which, as_ansi=as_ansi, add_wrap_markers=add_wrap_markers)