The range `A-aa-z` was too permissive and
includes special characters between `Z` and `a`.
Low impact, but fix to address an internally
reported code scanning alert.
As discussed in today's C++ analysis team meeting. `Opcode` is rarely used directly, so we'll just refer to the documentation for the corresponding `Instruction` class.
I've preserved the script in case we want to do a bulk change of all of the `Opcode` comments, but I don't expect it will be needed if we just add a new `Opcode` or two.
For every concrete `Opcode`, there is a corresponding `Instruction` class. Rather than duplicate all of the QLDoc by hand, I wrote a quick Python script to copy the QLDoc from `Instruction.qll` to `Opcode.qll`. I don't expect that we will need to do this often, so I'm not hooking it up to a PR check or anything like that, but I did commit the script itself in case we need it again.
