Returns a {@code CharSequence} from the {@code start} index (inclusive)
to the {@code end} index (exclusive) of this sequence.
param
start
the start offset of the sub-sequence. It is inclusive, that
is, the index of the first character that is included in the
sub-sequence.
param
end
the end offset of the sub-sequence. It is exclusive, that is,
the index of the first character after those that are included
in the sub-sequence
return
the requested sub-sequence.
throws
IndexOutOfBoundsException
if {@code start < 0}, {@code end < 0}, {@code start > end},
or if {@code start} or {@code end} are greater than the
length of this sequence.