tmux: C-v should start the selection if inactive

.config/tmux/tmux.conf

@@ -84,9 +84,18 @@ bind -r \} swap-pane -D
 
 # Enter copy-mode with Escape
 bind Escape copy-mode
-# Start selection (e.g. visual mode) with `v`
+
+# Start selection (i.e. visual mode) with `v`, and rectangle selection (i.e.
+# visual block mode) with `C-v`
+# TODO: mimic vims behaviour for visual mode cycling and toggling
 unbind -T copy-mode-vi v
 bind -T copy-mode-vi v send -X begin-selection
+unbind -T copy-mode-vi C-v
+bind -T copy-mode-vi C-v {
+	if -F "#{selection_active}" {} { send -X begin-selection }
+	send -X rectangle-toggle
+}
+
 # Yank into system clipboard
 # TODO: This breaks on repeatable movements (e.g. `y2e`)
 bind -T copy-mode-vi y \