Stubs are mostly generated from modules in shared-bindings. But in order
to generate the stub the c code has to be commented with the appropriate
type hints. If a module is located somewhere else (like
micropython.const) and/or there are not the appropriate doc comments, no
stub is generated for it. For these occassions we can create static
stubs in the stubs directory that can be used in circuitpython-stubs.
This also creates a stub for micropython.const and adds the static
stubs directory into the makefile stubs command.
