Moves forward to the next toggle (on or off) of the TextTag
tag, or to the
next toggle of any tag if
tag is null.
If no matching tag toggles are found, returns false, otherwise true. Does not return toggles located at this, only toggles after this. Sets this to the location of the toggle, or to the end of the buffer if no toggle is found.
a TextTag, or null
whether we found a tag toggle after this