Fix values-night/colors_aztec.xml properly

By annotating the 2 problematic color resources individually, instead of adjusting the exception rule with a too-broad regexp

See https://github.com/wordpress-mobile/WordPress-Android/pull/16285\#discussion_r846318394

WordPress/src/main/res/values-night/colors_aztec.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?><!--Overloaded Aztec colors. Remove after Aztec is phased out.-->
 <resources xmlns:tools="http://schemas.android.com/tools" tools:ignore="MissingDefaultResource">
-    <color name="format_bar_background">#282828</color>  <!-- 4dp elevated surface -->
-    <color name="format_bar_divider">?android:attr/listDivider</color>
+    <color name="format_bar_background" tools:ignore="UnusedResources">#282828</color>  <!-- 4dp elevated surface -->
+    <color name="format_bar_divider" tools:ignore="UnusedResources">?android:attr/listDivider</color>
     <color name="text">@color/material_on_surface_emphasis_high_type</color>
     <color name="title_color">@color/text</color>
     <color name="hint_text">@color/material_on_surface_emphasis_medium</color>

config/lint.xml

@@ -81,7 +81,7 @@
         <ignore path="**/WordPressEditor/**" />
         <ignore path="**/.gradle/caches/**" />
         <ignore path="**/generated/**" />
-        <ignore regexp=".*\/values\-([a-z]|[A-Z]|\-){2,6}\/.*\.xml$"/>
+        <ignore regexp=".*\/values\-([a-z]|[A-Z]|\-){2,6}\/strings\.xml$"/>
     </issue>
 
     <issue id="Typos" severity="error">