two small outstanding manual bugs

[Graham Percival]

http://www.lilypond.org/doc/v2.3/Documentation/user/out-www/lilypond/ 
Dynamics.html

\ppp and \pp are overwritten
\ff and \fff just look like fffff.

I could artificially space out this example (adding invisible 16ths),  
but IMO this bug should be fixed before 2.24.


http://www.lilypond.org/doc/v2.3/Documentation/user/out-www/lilypond/ 
Fingering-instructions.html

symbol for \thumb touches notehead.  This is probably a wontfix (yet)  
bug, though.