[lldb/script] Add type hints to scripted extension base classes (#209680)
This patch adds type annotations to every method (parameters and return
types) and every `self.<name>` attribute of the scripted extension base
classes shipped under `lldb/examples/python/templates/`. Extension
authors reading the base classes -- or an IDE navigating them -- can now
see the `lldb.SB*` contract each method exposes without having to
cross-reference the docstring.
`scripting extension generate` also picks the annotations up: derived
class docstrings advertise each inherited attribute together with its
declared type, and the generated method signatures carry their parameter
and return annotations too.
The classes covered are `ScriptedProcess`, `ScriptedThread`,
`ScriptedFrame`, `PassthroughScriptedProcess`,
`PassthroughScriptedThread`, `ScriptedFrameProvider`,
`ScriptedBreakpointResolver`, `ScriptedThreadPlan`, `ScriptedHook`,
`ScriptedPlatform`, and `OperatingSystem`.
Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>