public void addSecondaryHighlighter(Function function, DecompilerHighlighter highlighter) {
		userHighlights.addSecondaryHighlighter(function, highlighter);
	}
Adds the given secondary highlighter, but does not create any highlights.  All secondary
highlighters pertain to a given function.
@param function the function
@param highlighter the highlighter
Ghidra/Features/Decompiler/src/main/java/ghidra/app/decompiler/component/ClangHighlightController.java