[BUG] - documentation should include a general reference to all notation

## Description
The OML spec uses some notation that is not clearly identified up front or at all.

For example, 
* the `:>` symbol is not described the first time it is used. 
* `*` and `?` are never described. 
* `[]` in the context of [A | B]
* `()`

## Expected Behavior
All of the notations should be clearly identified up front before they are used.
