LRDOCS-532 URL title optimization

Here are a few notes for some changes I made in NumbersHeadersTask.java:

1. I had to increase the "MAX_ID_LEN" variable to 76 because I was getting StringIndexOutOfBounds exceptions when it was set to 75 (for "ant dist" in User Guide).

2. For the heading2 variable I added replace() for two other instances:
	-replace(" - ", "-") for titles like -> "### Domain Configuration - Continued"
	-replace('.', '-') for titles like -> "#### The portal-ext.properties file"

https://issues.liferay.com/browse/LRDOCS-532