[docs] Remove outdated svn/git information from hacking page

[AlexanderLanin]

Summary

The patch files section is redundant to https://llvm.org/docs/GettingStarted.html. There is nothing clang specific here. We are talking about a monorepo after all.
While it may seem nice to have one single clang page which explains everything, it's not:
It doesn't cover the topics in sufficient depth, it's redundant to other pages and it's hard to keep it up to date as we see with the svn instructions.

[aaron.ballman]

clang/www/hacking.html

278–279

Should this instead point to https://llvm.org/docs/GettingStarted.html#sending-patches to more closely match the original target anchor?

[AlexanderLanin]

clang/www/hacking.html

278–279

For a precise match yes, but I figured that one would need to start with git first of all as git is not mentioned anywhere else on the page.

[aaron.ballman]

clang/www/hacking.html

278–279

That's fair, but I think this whole section needs a bit more love than what's proposed. You cannot use svn diff for creating patches within a git repo. This text only makes sense when we were still doing the transition from svn to git, and the bit you're changing is the "oh yeah, or you can use git if you want" stuff. Now we need it to read "This is how you do this with git", at which point the checkout from git link isn't as useful as pointing out how you send a patch (which is the next logical step after forming a patch file).

Would you like to take a stab at updating this section rather than just the link?

[AlexanderLanin]

clang/www/hacking.html

278–279

Actually it would make sense to remove the 'Creating Patch Files' section here as that's redundant to https://llvm.org/docs/GettingStarted.html. There is nothing clang specific here. We are talking about a monorepo after all.
While it may seem nice to have one single clang page which explains everything, it's not:
It doesn't cover the topics in sufficient depth, it's redundant to other pages and it's hard to keep it up to date as we see with svn usage.

It's the same with:

• https://llvm.org/docs/Contributing.html#how-to-submit-a-patch
• https://llvm.org/docs/GettingStarted.html#sending-patches

which seem to simply have diverged over time.

[AlexanderLanin]

Not sure we can call this updated proposal 'love': it's definitely not the goal to have less documentation, just less redundancy.

I'll remove redundancies between those two in a separate pull request:

• https://llvm.org/docs/Contributing.html#how-to-submit-a-patch
• https://llvm.org/docs/GettingStarted.html#sending-patches

[aaron.ballman]

LGTM with a small typo fix. Do you need someone to commit this on your behalf?

clang/www/hacking.html

279

Getting started -> Getting Started (or, alternatively, getting started)

[AlexanderLanin]

Getting Started since it's Getting Started with the LLVM System

[AlexanderLanin]

In D72057#1802982, @aaron.ballman wrote:

LGTM with a small typo fix. Do you need someone to commit this on your behalf?

Yes, please. I cannot commit myself.
Alexander Lanin <[e-mail]>

[aaron.ballman]

Thank you for the patch! I've commit on your behalf in e5a56f2d50ce1939eba4fddbeb9c8e032db4fc95

clang/www/hacking.html

 </pre>
 
   <p>The statistic, "Unexpected Failures" (not shown if all tests pass), is the important one.</p>
 
   <!--=====================================================================-->
   <h2 id="patches">Creating Patch Files</h2>
   <!--=====================================================================-->
 
-  <p>To return changes to the Clang team, unless you have checkin
-  privileges, the preferred way is to send patch files
-  <a href="https://llvm.org/docs/Contributing.html#how-to-submit-a-patch">using LLVM's Phabricator</a> with an explanation of what the patch is for. Clang follows <a
-  href="https://llvm.org/docs/DeveloperPolicy.html">LLVM's developer policy</a>.
-  If your patch requires a wider discussion (for example, because it is an
-  architectural change), you can use the cfe-dev mailing list.</p>
-
-  <p>To create these patch files, change directory
-  to the llvm/tools/clang root and run:</p>
-
-  <pre>svn diff (relative path) >(patch file name)</pre>
-
-  <p>For example, for getting the diffs of all of clang:</p>
-
-  <pre>svn diff . >~/mypatchfile.patch</pre>
-
-  <p>For example, for getting the diffs of a single file:</p>
-
-  <pre>svn diff lib/Parse/ParseDeclCXX.cpp >~/ParseDeclCXX.patch</pre>
-
-  <p>Note that the paths embedded in the patch depend on where you run it,
-  so changing directory to the llvm/tools/clang directory is recommended.</p>
-
-  <p>It is also possible to <a href="https://llvm.org/docs/GettingStarted.html#sending-patches-with-git">use git to contribute</a> to Clang.</p>
+  <p>To contribute changes to Clang see
+    <a href="https://llvm.org/docs/GettingStarted.html#sending-patches">LLVM's Getting Started page</a></p>
 
   <!--=====================================================================-->
   <h2 id="irgen">LLVM IR Generation</h2>
   <!--=====================================================================-->
 
   <p>The LLVM IR generation part of clang handles conversion of the
     AST nodes output by the Sema module to the LLVM Intermediate
     Representation (IR). Historically, this was referred to as