bool = EndsWith(s$, substr$[, casesen, encoding])
s$ ends on the substring specified by substr$.
If it does, True is returned, False otherwise. If the optional argument casesen is set
to False, the strings do not have to match in case. casesen defaults to the global case
sensitive default mode set using IgnoreCase(). See IgnoreCase for details.
The optional encoding parameter can be used to set the character encoding
to use. This defaults to the default string encoding set using SetDefaultEncoding().
See Character encodings for details.
s$True or whatever default has been set using the IgnoreCase() command