Implement title_format

This implements the title_format command, with a new placeholder %shell
which gets substituted with the view type (xwayland, xdg_shell_v6 or
wl_shell).

Example config:

    for_window [title=".*"] title_format %title (class=%class instance=%instance shell=%shell)

1 files changed, 1 insertions, 0 deletions

diff --git a/include/sway/commands.h b/include/sway/commands.h
index 0732a90a..d39ac56c 100644
--- a/include/sway/commands.h
+++ b/include/sway/commands.h
@@ -144,6 +144,7 @@ sway_cmd cmd_splitt;
 sway_cmd cmd_splitv;
 sway_cmd cmd_sticky;
 sway_cmd cmd_swaybg_command;
+sway_cmd cmd_title_format;
 sway_cmd cmd_unmark;
 sway_cmd cmd_workspace;
 sway_cmd cmd_ws_auto_back_and_forth;