Improve TileRenderer Config Builder documentation per API review.

RelNote: "Document that the default value for
TileRenderer.Config.Builder#setTilesTheme is zero."

BUG: 330612472
Change-Id: Iced18d8f3dee7b441ba3f089c36bd8a60aacb770
diff --git a/wear/tiles/tiles-renderer/src/main/java/androidx/wear/tiles/renderer/TileRenderer.java b/wear/tiles/tiles-renderer/src/main/java/androidx/wear/tiles/renderer/TileRenderer.java
index 92dfccf..a1feb04 100644
--- a/wear/tiles/tiles-renderer/src/main/java/androidx/wear/tiles/renderer/TileRenderer.java
+++ b/wear/tiles/tiles-renderer/src/main/java/androidx/wear/tiles/renderer/TileRenderer.java
@@ -330,7 +330,8 @@
 
         /**
          * Returns the theme to use for this Tile instance. This can be used to customise things
-         * like the default font family.
+         * like the default font family. Defaults to zero (default theme) if not specified by {@link
+         * Builder#setTilesTheme(int)}.
          */
         public int getTilesTheme() {
             return mTilesTheme;
@@ -363,7 +364,7 @@
 
             /**
              * Sets the theme to use for this Tile instance. This can be used to customise things
-             * like the default font family.
+             * like the default font family. If not set, zero (default theme) will be used.
              */
             @NonNull
             public Builder setTilesTheme(@StyleRes int tilesTheme) {