Implement `log_separator' action keyword

features/actions/log_separator.feature

@@ -0,0 +1,9 @@
+Feature: `log_separator' action keyword
+
+  Scenario: logs a separator
+    Given uhwm is running with this run control file:
+      """
+      key(:f) { log_separator }
+      """
+    When I press the alt+f keys
+    Then the output must contain "- - - - - - - - - - - - - - - - - - - - - - -"

lib/uh/wm/actions_handler.rb

@@ -38,6 +38,10 @@ module Uh
         Process.waitpid pid
       end
 
+      def log_separator
+        log '- ' * 24
+      end
+
       def method_missing(m, *args, &block)
         if respond_to? m
           meth = layout_method m

spec/uh/wm/actions_handler_spec.rb

@@ -24,6 +24,13 @@ module Uh
         end
       end
 
+      describe '#log_separator' do
+        it 'logs a separator' do
+          expect(env).to receive(:log).with /(?:- ){20,}/
+          actions.log_separator
+        end
+      end
+
       describe '#layout_*' do
         it 'delegates messages to the layout with handle_ prefix' do
           expect(env.layout).to receive :handle_screen_sel