Sync up Pattern Javadoc with Java 8 Javadoc

[CodesAway]

For example, some syntax was added to Java's regex, which works in RegExPlus (since under the hood I'm using Java's regex engine). However, my documentation is outdated and doesn't specify the new syntax (such as \h and \v).

[CodesAway]

Might want to sync up to Java 14 due to Javadoc doclint