PyDefinitionsSearch.java: replace psi element on original element if it is from pyi and then search for overrides, inheritors etc.
PyiUtil.java: recursively get original element while it is in stub (see the comment) and tests testGoToImplementationNameReExportedThroughAssignmentInPyiStub, testGoToImplementationNameReExportedThroughAssignmentInPyiStubTwice
PyUtil.java: make different methods turnDirIntoInitPy, turnDirIntoInitPyi instead of only turnDirIntoInit to handle cases when the same directory contains __init__.pyi and __init__.py files (PY-54620)
GitOrigin-RevId: 8f0d8a8133548e1a9f52f93b42aa9cae2302e8d7