Add javadocs for local font family

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapboxMapOptions.java

@@ -594,6 +594,7 @@ public class MapboxMapOptions implements Parcelable {
    * <p>
    * The font family argument is passed to {@link android.graphics.Typeface#create(String, int)}.
    * Default system fonts are defined in &#x27;/system/etc/fonts.xml&#x27;
+   * Default font for local ideograph font family is "sans-serif".
    *
    * @param fontFamily font family for local ideograph generation.
    * @return This
@@ -887,6 +888,7 @@ public class MapboxMapOptions implements Parcelable {
   /**
    * Returns the font-family for locally overriding generation of glyphs in the
    * &#x27;CJK Unified Ideographs&#x27; and &#x27;Hangul Syllables&#x27; ranges.
+   * Default font for local ideograph font family is "sans-serif".
    *
    * @return Local ideograph font family name.
    */

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/snapshotter/MapSnapshotter.java

@@ -183,6 +183,7 @@ public class MapSnapshotter {
      * <p>
      * The font family argument is passed to {@link android.graphics.Typeface#create(String, int)}.
      * Default system fonts are defined in &#x27;/system/etc/fonts.xml&#x27;
+     * Default font for local ideograph font family is "sans-serif".
      *
      * @param fontFamily font family for local ideograph generation.
      * @return the mutated {@link Options}
@@ -250,7 +251,8 @@ public class MapSnapshotter {
     }
 
     /**
-     * @return the font family used for locally generating ideographs
+     * @return the font family used for locally generating ideographs,
+     * Default font for local ideograph font family is "sans-serif".
      */
     public String getLocalIdeographFontFamily() {
       return localIdeographFontFamily;