public boolean renameRegister(String oldName, String newName) {
		if (registerMap.containsKey(newName)) {
			return false;
		}
		Register register = registerMap.get(oldName);
		if (register == null) {
			return false;
		}
		register.rename(newName);
		removeRegisterFromNameMap(oldName);
		addRegisterToNameMap(newName, register);
		return true;
	}
Rename a register.  This allows generic register names declared within the language 
specification (*.slaspec) to be renamed for a processor variant specification (*.pspec).
@param oldName original register name
@param newName new register name
@return true if rename was successful, else false
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/lang/RegisterBuilder.java