Issue #7573: update doc for MissingOverride

[HuGanghui]

Issue #7573: update doc for MissingOverride

Ouput of default example:
$ cat config.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
        "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
        "https://checkstyle.org/dtds/configuration_1_3.dtd">
<module name="Checker">
    <module name="TreeWalker">
        <module name="MissingOverride"/>
    </module>
</module>

$ cat Test.java

class Test extends SuperClass {

    /** {@inheritDoc} */
    @Override
    public void test1() { // OK

    }

    /** {@inheritDoc} */
    public void test2() { // violation, should be annotated with @Override

    }

    /** {@inheritDoc} */
    private void test3() { // violation, using the @inheritDoc tag on private method that is not valid

    }

    /** {@inheritDoc} */
    public static void test4() { // violation, using the @inheritDoc tag on static method that is not valid

    }

}

$ RUN_LOCALE="-Duser.language=en -Duser.country=US"
$ java $RUN_LOCALE -jar /var/tmp/checkstyle-8.31-SNAPSHOT-all.jar -c config.xml Test2.java
Starting audit...
[ERROR] /var/tmp/Test.java:10: Must include @java.lang.Override annotation when {@inheritdoc} Javadoc tag exists. [MissingOverride]
[ERROR] /var/tmp/Test.java:15: The Javadoc {@inheritdoc} tag is not valid at this location. [MissingOverride]
[ERROR] /var/tmp/Test.java:20: The Javadoc {@inheritdoc} tag is not valid at this location. [MissingOverride]
Audit done.
Checkstyle ends with 3 errors.

Ouput of configure the check for the javaFiveCompatibility mode:
$ cat config.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
        "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
        "https://checkstyle.org/dtds/configuration_1_3.dtd">
<module name="Checker">
    <module name="TreeWalker">
        <module name="MissingOverride">
            <property name="javaFiveCompatibility"
                      value="true"/>
        </module>
    </module>
</module>

$ cat Test.java

class Test1 {

    /** {@inheritDoc} */
    public void equals() { // violation, should be annotated with @Override

    }
}

interface Test2 {

    /** {@inheritDoc} */
    public abstract void test(); // violation, should be annotated with @Override

}

class Test3 extends SuperClass {

    /** {@inheritDoc} */
    public void test() { // OK, is ignored because class extends other class

    }
}

class Test4 implements SuperInterface {

    /** {@inheritDoc} */
    public void test() { // OK, is ignored because class implements interface

    }
}

class Test5 {
    Runnable r = new Runnable() {

        /** {@inheritDoc} */
        public void run() { // OK, is ignored because class is anonymous class

        }
    };
}

$ RUN_LOCALE="-Duser.language=en -Duser.country=US"
$ java $RUN_LOCALE -jar /var/tmp/checkstyle-8.31-SNAPSHOT-all.jar -c config.xml Test.java
Starting audit...
[ERROR] /var/tmp/Test.java:4: Must include @java.lang.Override annotation when {@inheritdoc} Javadoc tag exists. [MissingOverride]
[ERROR] /var/tmp/Test.java:12: Must include @java.lang.Override annotation when {@inheritdoc} Javadoc tag exists. [MissingOverride]
Audit done.
Checkstyle ends with 2 errors.

[HuGanghui]

I need some help, I don't why the travis-ci test fail

[rnveach]

Please rebase on latest master to resolve CI spellchecker issue.

[HuGanghui]

In my local computer, all tests pass, but wercker/build failed and I can't see details, so please give me some help. @strkkk

[rnveach]

Please fix failing travis. Wercker has to be ignored now as we are trying to fix an issue with it.

[strkkk]

@HuGanghui please also update first post

[strkkk]

last minor

[strkkk]

@HuGanghui I have added review comments above, please take a look

[strkkk]

Can be merged after CI pass