Update requirements from discussion

RFC-0026-logging-system.md

@@ -38,6 +38,12 @@ Create a message logging system for PyTorch with the following requirements:
   - **Prototype**: Emitted when a prototype feature is called. See
     [PyTorch feature classifications](https://pytorch.org/blog/pytorch-feature-classification-changes/)
 
+  - TODO: Should all the classic Python errors and warnings (`TypeError`,
+    `ValueError`, `NotImplementedError`, `DeprecationWarning`, etc) have their
+    own message class? Or are those separate from our concept of a message
+    class, and any message class is allowed to raise any Python exception or
+    warning type?
+
 * Continue using warning/error APIs that currently exist in PyTorch wherever
   possible. For instance, `TORCH_CHECK`, `TORCH_WARN`, and `TORCH_WARN_ONCE`
   should continue to be used in C++
@@ -47,30 +53,41 @@ Create a message logging system for PyTorch with the following requirements:
 
 * Creating new message classes and severity levels should be easy
 
-* Settings to turn warnings for a specific message class into errors
+* Ability to turn warnings into errors. This is already possible with the
+  Python `warnings` module filter, but the PyTorch docs should mention it and
+  we should probably have unit tests for it.
+  See [documentation](https://docs.python.org/3/library/warnings.html#the-warnings-filter)
 
 * Settings to disable specific message classes and severity levels
 
-  - TODO: However, most errors should not be disableable, right? Perhaps only
+  - TODO: Most errors should not be disableable, right? Perhaps only
     some message classes should allow disabling or downgrading errors. For
     instance, currently in PyTorch, we can downgrade a nondeterministic error
     to a warning, but we wouldn't want to downgrade an error from invalid
     arguments given to an operation.
 
+  - Disabling warnings in Python should already be possible with the `warnings`
+    module filter. See [documentation](https://docs.python.org/3/library/warnings.html#the-warnings-filter).
+    There is no similar system in C++ at the moment, and building one is probably
+    low priority.
+
+  - Filtering out **Info** severity messages would also be nice to have, since
+    excessive printouts can degrade the user experience. Related to
+    issue [#68768](https://github.com/pytorch/pytorch/issues/68768)
+
 * Settings to avoid emitting duplicate messages generated by multiple
-  `torch.distribted` ranks (related to issue
-  [#68768](https://github.com/pytorch/pytorch/issues/68768))
+  `torch.distributed` ranks. Related to issue
+  [#68768](https://github.com/pytorch/pytorch/issues/68768)
 
-* Ability to make a particular warning only warn once
+* Ability to make a particular warning only warn once. Warn-once should be the
+  default in most cases.
 
   - NOTE: Currently `TORCH_WARN_ONCE` does this in C++, but there is no Python
     equivalent
 
-  - TODO: Should there be a setting to turn a warn-always into a warn-once for
+  - TODO: Should there be a setting to turn a warn-once into a warn-always for
     a given message class and vice versa?
 
-  - TODO: Should warn-once be its own separate severity level?
-
 * Settings can be changed from Python, C++, or environment variables
 
   - Filtering warnings with Python command line arguments should