window-rules: support title criteria

Example config:

    <windowRules>
      <windowRule identifier="foot" title="max">
        <action name="Maximize"/>
      </windowRule>
    </windowRules>

Observe that:

- `foot -T foo` starts maximized
- `xterm -T foo` starts normal

docs/labwc-config.5.scd

@@ -347,7 +347,7 @@ defined as shown below.
 <windowRules>
 
   <!-- Action -->
-  <windowRule identifier="">
+  <windowRule identifier="" title="">
     <action name=""/>
   </windowRule>
 
@@ -359,15 +359,18 @@ defined as shown below.
 
 *Actions*
 
-*<windowRules><windowRule identifier="">*
+*<windowRules><windowRule identifier="" title="">*
 	Define a window rule for any window which matches the criteria defined
-	by the attribute *identifier*. Matching against patterns with '\*'
-	(wildcard) and '?' (joker) is supported. Pattern matching is
-	case-insensitive.
+	by the attributes *identifier* or *title*. If both are defined, AND
+	logic is used, so both have to match.
+	Matching against patterns with '\*' (wildcard) and '?' (joker) is
+	supported. Pattern matching is case-insensitive.
 
 	*identifier* relates to app_id for native Wayland windows and WM_CLASS
 	for XWayland clients.
 
+	*title* is the title of the window.
+
 *Properties*
 
 Property values can be *yes*, *no* or *default*.

docs/rc.xml.all

@@ -376,11 +376,19 @@
   </libinput>
 
   <!--
+    Window Rules
+      - Criteria can consist of 'identifier' or 'title' or both (in which case
+        AND logic is used).
+      - 'identifier' relates to app_id for native Wayland windows and WM_CLASS
+        for XWayland clients.
+      - Matching against patterns with '*' (wildcard) and '?' (joker) is
+        supported. Pattern matching is case-insensitive.
+
   <windowRules>
-    <windowRule identifier="*">
-      <action name="Maximize" />
-    </windowRule>
-    <windowRule identifier="some-application" serverDecoration="yes" />
+    <windowRule identifier="*"><action name="Maximize"/></windowRule>
+    <windowRule identifier="foo" serverDecoration="yes"/>
+    <windowRule title="bar" serverDecoration="yes"/>
+    <windowRule identifier="baz" title="quax" serverDecoration="yes"/>
   </windowRules>
   -->