Add information about defining and inserting parameterized rule sets

[mint-thompson]

Add information about parameterized rule sets. This results in changes to the following sections:

• 3.5.7 "Insert Rules" now contains two subsections: one for inserting a rule set without parameters, and one for inserting a rule set with parameters.
• 3.6.8 "Defining Rule Sets" now contains two subsections: one for defining a rule set without parameters, and one for defining a rule set with parameters.
• 3.8 "Appendix: Formal Grammar" now contains two subsections, as the formal grammar has been split into separate files for the parser and the lexer.