Put loaded modules (plugins) into sys.modules

With this, the plugins are accessible from other modules without
requiring an explicit import. This was the default behaviour of the
previous pre-3.10 loader.

Without this, an import call would re-import the plugin making the
first and the second ones different from Python's perspective even if
they are both the same. This breaks pickle.

Author: eldipa

byexample/init.py

@@ -112,6 +112,8 @@ def load_modules(dirnames, cfg):
             spec = importer.find_spec(name)
             module = importlib.util.module_from_spec(spec)
             spec.loader.exec_module(module)
+
+            sys.modules[name] = module
         except Exception as e:
             clog().info(
                 "From '%s' loading '%s'...failed: %s", path, name, str(e)