New highlighter for Ruby's ERB and HTML embedded ERB

Ruby code inside ERB tags (whether in plain or HTML environment) is highlighted
via the ruby.jsf colorer.

ftyperc

@@ -860,3 +860,11 @@
 -syntax whitespace
  --force
  --spaces
+
+ plain ERB
+*.erb
+-syntax erb
+
+ .html.erb
+*.html.erb
+-syntax htmlerb