docs: modernize docstrings across the repository (#1682)

Comprehensive docstring cleanup across the repository — fix Sphinx
cross-references, Python REPL continuation syntax, stale class names,
and modernize the IotBulb docstring to use the
`Module.Light`/`Module.LightPreset` interface.

kasa/iot/iotplug.py

@@ -18,12 +18,12 @@ _LOGGER = logging.getLogger(__name__)
 class IotPlug(IotDevice):
     r"""Representation of a TP-Link Smart Plug.
 
-    To initialize, you have to await :func:`update()` at least once.
+    To initialize, you have to await :meth:`update()` at least once.
     This will allow accessing the properties using the exposed properties.
 
     All changes to the device are done using awaitable methods,
     which will not change the cached values,
-    but you must await :func:`update()` separately.
+    but you must await :meth:`update()` separately.
 
     Errors reported by the device are raised as :class:`KasaException`\s,
     and should be handled by the user of the library.