Add doc-typehints to class properties found by the PropertyDocumentation
sniff to improve the documentation.
Once the sniff is enabled it avoids that new code is missing type
declarations. This is focused on documentation and does not change code.
Change-Id: Idf17719c875466810313f0fbbf16bc67f3e40059
Do not allow optional path parameters or empty path segments
within the path. Handlers may still consider a path parameter
to be non-required. Normally this is when a handler services
multiple routes, and not all routes supply all parameters.
Bug: T359652
Change-Id: I4f82ee2b6ec5b631249d26496688e5f42696c1d0