[docs] Update release notes with items related to Flang

[kiranchandramohan]

LGTM. I have one minor question. Please address only if others point out the same thing.

llvm/docs/ReleaseNotes.rst

58

Is alongside Clang important? Should we say something about the default behaviour (i.e parse, unparse and use external compiler to generate code)?

[DavidSpickett]

Perhaps a silly question, this is for the llvm 13 branch right?

[kiranchandramohan]

In D109317#2985153, @DavidSpickett wrote:

Perhaps a silly question, this is for the llvm 13 branch right?

Yes, it is for the release branch. Hope it is not too late. I had volunteered but missed it in the last two weeks.

[awarzynski]

In D109317#2985153, @DavidSpickett wrote:

Perhaps a silly question, this is for the llvm 13 branch right?

Yes. I agree that this is not 100% clear (other than from the updated file itself). Is there any way to make this more visible?

[DavidSpickett]

Yes, it is for the release branch. Hope it is not too late. I had volunteered but missed it in the last two weeks.

You're just in time I think: https://lists.llvm.org/pipermail/cfe-dev/2021-August/068723.html

Yes. I agree that this is not 100% clear (other than from the updated file itself). Is there any way to make this more visible?

I don't see one, doesn't matter just wanted to double check.

[awarzynski]

llvm/docs/ReleaseNotes.rst

58

Is alongside Clang important?

Good point, let me remove this.

Should we say something about the default behaviour (i.e parse, unparse and use external compiler to generate code)?

Wouldn't flang/docs/ReleaseNotes.md be more suitable for this level of detail? Also, there has been no changes between LLVM 12 and 13 here, so I'm not sure whether we should include this. If there are no further comments on this today, I will skip it and merge as is.

[awarzynski]

Remove "alongside Clang"

[DavidSpickett]

Deadline was extended to Friday: https://lists.llvm.org/pipermail/llvm-dev/2021-September/152525.html

[tstellar]

In D109317#2988927, @DavidSpickett wrote:

Deadline was extended to Friday: https://lists.llvm.org/pipermail/llvm-dev/2021-September/152525.html

The deadline does not apply to release note changes, they can be committed any time before the final release.

[awarzynski]

Merged into the release/13.x branch: https://github.com/llvm/llvm-project/commit/181739213aa00de40a5bc6fbb1c578ce25b78d39. Closing manually.

llvm/docs/ReleaseNotes.rst

.. NOTE
    -------------------
 
    Makes programs 10x faster by doing Special New Thing.
 
 * Windows Control-flow Enforcement Technology: the ``-ehcontguard`` option now
   emits valid unwind entrypoints which are validated when the context is being
   set during exception handling.
 
+* Flang is now included in the binary packages released by LLVM.
+
 Changes to the LLVM IR
 ----------------------
 
 * The ``inalloca`` attribute now has a mandatory type field, similar
   to ``byval`` and ``sret``.
 
 * The opaque pointer type ``ptr`` has been introduced. It is still in the
   process of being worked on and should not be used yet.