Update my grammar notes to handle type annotations and correct logic-ops.
Variables in the grammar can’t be in our (fixed) set of infix names.

The infix names are +, -, *, /, div, mod and before.

Maybe there are more.
Some work towards parsing types, stymied by TFL bug.

See http://github.com/mn200/HOL/issues/108 for bug.

It’s possible it’s not TFL’s fault.