replaceRange

Replaces the characters in the range [start, end) with the given string.

Example:

    var sb = new StringBuilder.withString ("Hello World");
    sb.replaceRange (6, 11, "Vala");
    assert (sb.toString () == "Hello Vala");

Parameters:

start	the start index (inclusive).
end	the end index (exclusive).
s	the replacement string.

Returns:

this StringBuilder for chaining.