Inserts characters in a subsequence of the specified character sequence csq into this string builder at the specified index and returns this instance.
The inserted characters go in the same order as in the csq character sequence, starting at index.
index - the position in this string builder to insert at.
csq - the character sequence from which a subsequence is inserted. If csq is
then characters will be inserted as if csq contained the four characters
start - the beginning (inclusive) of the subsequence to insert.
end - the end (exclusive) of the subsequence to insert.
IndexOutOfBoundsException - or IllegalArgumentException when start or end is out of range of the csq character sequence indices or when
start > end.
IndexOutOfBoundsException - if index is less than zero or greater than the length of this string builder.