protected static class SpaceReducer.Tag
extends Object
this is a helper class that can check if a tag was opened or closed in a line of text
It first removes all bodyless versions of the tag from the line, and then counts all opening and
closing occurrences of the tag.
This will not work if an opening or closing tag is partly written on the next line, so it's not perfect.
have no body
can be opened and closed multiple times in one line.