Add examples to show depth

[積丹尼 Dan Jacobson]

(info "(find) Directories") says

 -- Option: -maxdepth levels
     Descend at most LEVELS (a non-negative integer) levels of
     directories below the command line arguments.  '-maxdepth 0' means
     only apply the tests and actions to the command line arguments.

 -- Option: -mindepth levels
     Do not apply any tests or actions at levels less than LEVELS (a
     non-negative integer).  '-mindepth 1' means process all files
     except the command line arguments.

OK that is great, but not clear without examples.

Something like
$ find -name Makefile
./comm/radio/radioscanningtw/maps/Makefile
./comm/air/m750/programs/a/Makefile
./comm/air/routes/programs/Makefile
$ find -maxdepth 4 -name Makefile
$ find -maxdepth 5 -name Makefile
./comm/radio/radioscanningtw/maps/Makefile
./comm/air/routes/programs/Makefile
etc.