Fix xml tag in comment

     * This class parses Keyboard XML file and eventually build a Keyboard.

     * The Keyboard XML file looks like:

     * <pre>

     *   >!-- xml/keyboard.xml --<

     *   >Keyboard keyboard_attributes*<

     *     >!-- Keyboard Content --<

     *     >Row row_attributes*<

     *       >!-- Row Content --<

     *       >Key key_attributes* /<

     *       >Spacer horizontalGap="32.0dp" /<

     *       >include keyboardLayout="@xml/other_keys"<

     *   <!-- xml/keyboard.xml -->

     *   <Keyboard keyboard_attributes*>

     *     <!-- Keyboard Content -->

     *     <Row row_attributes*>

     *       <!-- Row Content -->

     *       <Key key_attributes* />

     *       <Spacer horizontalGap="32.0dp" />

     *       <include keyboardLayout="@xml/other_keys">

     *       ...

     *     >/Row<

     *     >include keyboardLayout="@xml/other_rows"<

     *     </Row>

     *     <include keyboardLayout="@xml/other_rows">

     *     ...

     *   >/Keyboard<

     *   </Keyboard>

     * </pre>

     * The XML file which is included in other file must have >merge< as root element,

     * The XML file which is included in other file must have <merge> as root element,

     * such as:

     * <pre>

     *   >!-- xml/other_keys.xml --<

     *   >merge<

     *     >Key key_attributes* /<

     *   <!-- xml/other_keys.xml -->

     *   <merge>

     *     <Key key_attributes* />

     *     ...

     *   >/merge<

     *   </merge>

     * </pre>

     * and

     * <pre>

     *   >!-- xml/other_rows.xml --<

     *   >merge<

     *     >Row row_attributes*<

     *       >Key key_attributes* /<

     *     >/Row<

     *   <!-- xml/other_rows.xml -->

     *   <merge>

     *     <Row row_attributes*>

     *       <Key key_attributes* />

     *     </Row>

     *     ...

     *   >/merge<

     *   </merge>

     * </pre>

     * You can also use switch-case-default tags to select Rows and Keys.

     * <pre>

     *   >switch<

     *     >case case_attribute*<

     *       >!-- Any valid tags at switch position --<

     *     >/case<

     *   <switch>

     *     <case case_attribute*>

     *       <!-- Any valid tags at switch position -->

     *     </case>

     *     ...

     *     >default<

     *       >!-- Any valid tags at switch position --<

     *     >/default<

     *   >/switch<

     *     <default>

     *       <!-- Any valid tags at switch position -->

     *     </default>

     *   </switch>

     * </pre>

     * You can declare Key style and specify styles within Key tags.

     * <pre>

     *     >switch<

     *       >case mode="email"<

     *         >key-style styleName="f1-key" parentStyle="modifier-key"

     *     <switch>

     *       <case mode="email">

     *         <key-style styleName="f1-key" parentStyle="modifier-key"

     *           keyLabel=".com"

     *         /<

     *       >/case<

     *       >case mode="url"<

     *         >key-style styleName="f1-key" parentStyle="modifier-key"

     *         />

     *       </case>

     *       <case mode="url">

     *         <key-style styleName="f1-key" parentStyle="modifier-key"

     *           keyLabel="http://"

     *         /<

     *       >/case<

     *     >/switch<

     *         />

     *       </case>

     *     </switch>

     *     ...

     *     >Key keyStyle="shift-key" ... /<

     *     <Key keyStyle="shift-key" ... />

     * </pre>

     */