Update Symbology Documentation

[MattReimer]

Since we wrote the documentation for the web symbology things have changed a bit. The docs here

• https://rave.riverscapes.net/Technical_Reference/Symbology/webrave_symbology.html

Are out of date and need updating.

The most current documentation for symbolizing web layers is here:

• https://github.com/Riverscapes/RiverscapesXML/blob/master/docs/Symbology/webRAVEVectors.md
• https://github.com/Riverscapes/RiverscapesXML/blob/master/docs/Symbology/webRAVERasters.md