Add option to use custom modal mode status bar icon

README.md

@@ -282,6 +282,17 @@ use. For example, if you press `w` the status bar will change from the modal
 command icon `[=]` to `[w]` (the window command). If you now further press `s`,
 it will update to `[ws]` to signify the split window command sequence and so on.
 
+### Set custom status bar modal mode icon
+
+The option `@modal-cmd-icon` can be used to specify any string, which will be
+the left status bar icon to indicate that modal mode is in use. For example, to
+use a circle as icon (note the padding at the beginning for a more aesthetically
+centering in the status bar):
+
+```
+set -g @modal-cmd-icon " 🟢"
+```
+
 ### Yes/no prompt
 
 **DEPRECATED**

tmux-modal.tmux

@@ -152,6 +152,13 @@ elif ! parse_yn_opt "$SHOW_CMD_KEYS_VAL" $SHOW_CMD_KEYS_OPT; then
     exit 22
 fi
 
+# Modal mode status bar icon.
+KT_CMD_ICON_OPT=@modal-cmd-icon
+KT_CMD_ICON_VAL=$(tmux show-options -g -v -q $KT_CMD_ICON_OPT)
+if [ -z "$KT_CMD_ICON_VAL" ]; then
+    KT_CMD_ICON_VAL="[=]"
+fi
+
 # Create keybinding file to be sourced by tmux.
 
 KBD_FILE="$CURRENT_DIR/.kbd.conf"
@@ -374,7 +381,7 @@ fi
 
 # Prepend left status bar with KT_CMD_ICON if our key tables are in use.
 # Determine this by checking if current key table starts with our prefix.
-KT_CMD_ICON="[=]"
+KT_CMD_ICON=$KT_CMD_ICON_VAL
 STATUS_LEFT=`
 `'#{'`
   `'?#{==:'$KT_PREFIX'-,'`