Fix commit e40d2cb3af (Xcode: Add embed resources support, 2023-07-31,
v3.28.0-rc1~281^2). The implementation should not name the `_PATH`
suffix explicitly. That variant is automatically handled by
`cmGlobalXCodeGenerator::AddEmbeddedObjects`.
This commit also prepares for embedding things other than
frameworks. In the future, we may want to embed resources and
other types supported by Xcode, so the target properties have
been documented in a way that clearly signals the future intent.
