PEP 784: Updates to timeline and RFC reference (#4352)

* Add link to RFC 8478

* Add updated timeline verbiage

* Fix DeprecationWarnings

Author: emmatyping

peps/pep-0784.rst

@@ -44,7 +44,8 @@ significantly faster than LZMA.
 Zstandard has seen `widespread adoption`_ in many different areas of computing.
 The numerous hardware implementations demonstrate long-term commitment to
 Zstandard and an expectation that Zstandard will stay the *de facto* choice for
-compression for years to come. Zstandard compression is also implemented in
+compression for years to come. This is further evidenced by Zstandard's IETF
+standardization in :rfc:`8478`. Zstandard compression is also implemented in
 both the ZFS_ and Btrfs_ filesystems.
 
 Zstandard's highly efficient compression has supplanted other modern
@@ -231,11 +232,13 @@ Existing modules will emit a ``DeprecationWarning`` in the Python
 release following the last Python without the ``compression`` module leaving
 support. For example, if the ``compression`` namespace is introduced in 3.14,
 then the ``DeprecationWarnings`` would be emitted in 3.19, the next release
-after 3.13 reaches end of life. Following the standard deprecation timeline
-specified in :pep:`387`, in Python 3.24 the existing modules will be removed
-and code must use the ``compression`` sub-modules. The documentation for these
-modules will be updated to discuss the planned deprecation and removal
-timelines.
+after 3.13 reaches end of life. These warnings would begin five years after the
+introduction of ``compression`` namespace. In accordance with :pep:`387`, in
+Python 3.24, five years after the ``DeprecationWarnings`` are added and ten
+years after the new ``compression`` namespace is introduced, the existing
+modules will be removed and code must use the ``compression`` sub-modules. The
+documentation for these modules will be updated to discuss the planned
+deprecation and removal timelines.
 
 
 Backwards Compatibility