[llvm] [llvm][Docs] Update MyFirstTypoFix doc (PR #79149)

[Alex Bradbury via llvm-commits]

================
@@ -254,148 +247,133 @@ so it runs them all.
 
 .. code:: console
 
-   ********************
-   Testing Time: 408.84s
    ********************
    Failing Tests (1):
        Clang :: SemaCXX/warn-infinite-recursion.cpp
 
 Well, that makes sense… and the test output suggests it's looking for
 the old string "call itself" and finding our new message instead.
-Note that more tests may fail in a similar way as new tests are
-added time to time.
+Note that more tests may fail in a similar way as new tests are added
+over time.
 
 Let's fix it by updating the expectation in the test.
 
 .. code:: console
 
    $ vi ../clang/test/SemaCXX/warn-infinite-recursion.cpp
 
-Everywhere we see `// expected-warning{{call itself}}` (or something similar
+Everywhere we see ``// expected-warning{{call itself}}`` (or something similar
 from the original warning text), let's replace it with
-`// expected-warning{{to understand recursion}}`.
+``// expected-warning{{to understand recursion}}``.
 
 Now we could run **all** the tests again, but this is a slow way to
 iterate on a change! Instead, let's find a way to re-run just the
 specific test. There are two main types of tests in LLVM:
 
--  **lit tests** (e.g. SemaCXX/warn-infinite-recursion.cpp).
+-  **lit tests** (e.g. ``SemaCXX/warn-infinite-recursion.cpp``).
 
 These are fancy shell scripts that run command-line tools and verify the
 output. They live in files like
-clang/**test**/FixIt/dereference-addressof.c. Re-run like this:
+``clang/**test**/FixIt/dereference-addressof.c``. Re-run like this:
 
 .. code:: console
 
    $ bin/llvm-lit -v ../clang/test/SemaCXX/warn-infinite-recursion.cpp
 
--  **unit tests** (e.g. ToolingTests/ReplacementTest.CanDeleteAllText)
+-  **unit tests** (e.g. ``ToolingTests/ReplacementTest.CanDeleteAllText``)
 
 These are C++ programs that call LLVM functions and verify the results.
 They live in suites like ToolingTests. Re-run like this:
 
 .. code:: console
 
-   $ ninja ToolingTests && tools/clang/unittests/Tooling/ToolingTests
-   --gtest_filter=ReplacementTest.CanDeleteAllText
+   $ ninja ToolingTests && tools/clang/unittests/Tooling/ToolingTests --gtest_filter=ReplacementTest.CanDeleteAllText
 
 
 Commit locally
 --------------
 
 We'll save the change to a local git branch. This lets us work on other
 things while the change is being reviewed. Changes should have a
-description, to explain to reviewers and future readers of the code why
+title and description, to explain to reviewers and future readers of the code why
 the change was made.
 
+For now, we'll only add a title.
+
 .. code:: console
 
    $ git checkout -b myfirstpatch
-   $ git commit -am "[Diagnostic] Clarify -Winfinite-recursion message"
+   $ git commit -am "[clang][Diagnostic] Clarify -Winfinite-recursion message"
 
-Now we're ready to send this change out into the world! By the way,
-There is an unwritten convention of using tag for your commit. Tags
-usually represent modules that you intend to modify. If you don't know
-the tags for your modules, you can look at the commit history :
-https://github.com/llvm/llvm-project/commits/main.
+Now we're ready to send this change out into the world!
 
+The ``[clang]`` and ``[Diagnostic]`` are what we call tags. This loose convention
----------------
asb wrote:

Feels like this is missing a word, perhaps "and [Diagnostic] prefixes are what we call tags"?

https://github.com/llvm/llvm-project/pull/79149