Fix documentation strings in Android Notification (#445)

* Fix doc strings

* Fix code font

* Fix punctuation

Author: lahirumaramba

src/main/java/com/google/firebase/messaging/AndroidConfig.java

@@ -198,7 +198,7 @@ public Builder setNotification(AndroidNotification notification) {
     }
 
     /**
-     * Sets the {@link AndroidFcmOptions}, which will override values set in the {@link FcmOptions}
+     * Sets the {@link AndroidFcmOptions}, which overrides values set in the {@link FcmOptions}
      * for Android messages.
      */
     public Builder setFcmOptions(AndroidFcmOptions androidFcmOptions) {
@@ -207,7 +207,7 @@ public Builder setFcmOptions(AndroidFcmOptions androidFcmOptions) {
     }
 
     /**
-     * Sets the direct_boot_ok flag, If set to true, messages will be allowed to be delivered to 
+     * Sets the {@code direct_boot_ok} flag. If set to true, messages are delivered to 
      * the app while the device is in direct boot mode.
      */
     public Builder setDirectBootOk(boolean directBootOk) {