Incorrect Man pages of Javadocs tool

While changing our build tools we were stumbling on outdated Man pages.

Although HTML4 support was already removed from Javadoc, the Man pages still show:
- default is HTML4 (incorrect) - this is not even true in LTS release 11
- shows options -html4 (no longer existing) and -html5 (now new default, but obsolete to show at all)
- allows to enable frames, which does not work

Interesting source parts: https://hg.openjdk.java.net/jdk/jdk/file/51fb05ec531d/src/jdk.javadoc/share/man/javadoc.1

Specifically:
- https://hg.openjdk.java.net/jdk/jdk/file/51fb05ec531d/src/jdk.javadoc/share/man/javadoc.1#l688
- https://hg.openjdk.java.net/jdk/jdk/file/51fb05ec531d/src/jdk.javadoc/share/man/javadoc.1#l636