[lld-macho][docs] Cosmetic changes

[int3]

Summary

1. Fixed rST hyperlink syntax
2. Renamed LD64 -> ld64
3. Moved up the -no_deduplicate section so it is right under the section talking about how our default dedup behavior differs; IMO it makes more sense to read them in that order
4. De-bullet-listed some other sections so we have less whitespace in the rendered page
5. Since the Mach-O LLD Port page has only one sub-page, don't render an entire toctree with just one item. Use a "See also" box instead.

[michaeleisel]

lgtm

[int3]

you could approve it ;)

[int3]

@ributzka are you sure you actually want to be added to every LLD-MachO diff

lld/docs/MachO/index.rst

 Mach-O LLD Port
 ===============
 
 LLD is a linker from the LLVM project that is a drop-in replacement
 for system linkers and runs much faster than them. It also provides
 features that are useful for toolchain developers. This document
 will describe the Mach-O port.
 
 Features
 --------
 
 - LLD is a drop-in replacement for Apple's Mach-O linker, ld64, that accepts the
   same command line arguments.
 
 - LLD is very fast. When you link a large program on a multicore
-  machine, you can expect that LLD runs more than twice as fast as the ld64 linker.
+  machine, you can expect that LLD runs more than twice as fast as the ld64
+  linker.
 
 Download
 --------
 
 LLD is available as a pre-built binary by going to the `latest release <https://github.com/llvm/llvm-project/releases>`_,
 downloading the appropriate bundle (``clang+llvm-<version>-<your architecture>-<your platform>.tar.xz``),
 decompressing it, and locating the binary at ``bin/ld64.lld``. Note
 that if ``ld64.lld`` is moved out of ``bin``, it must still be accompanied
 by its sibling file ``lld``, as ``ld64.lld`` is technically a symlink to ``lld``.
 
 Build
 -----
 
 The easiest way to build LLD is to
 check out the entire LLVM projects/sub-projects from a git mirror and
-build that tree. You need `cmake` and of course a C++ compiler.
+build that tree. You need ``cmake`` and of course a C++ compiler.
 
 .. code-block:: console
 
   $ git clone https://github.com/llvm/llvm-project llvm-project
   $ mkdir build
   $ cd build
   $ cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_PROJECTS='lld' ../llvm-project/llvm
   $ ninja check-lld-macho
 
 Then you can find output binary at ``build/bin/ld64.lld``. Note
 that if ``ld64.lld`` is moved out of ``bin``, it must still be accompanied
 by its sibling file ``lld``, as ``ld64.lld`` is technically a symlink to ``lld``.
 
 Using LLD
 ---------
 
 LLD can be used by adding ``-fuse-ld=/path/to/ld64.lld`` to the linker flags.
 For Xcode, this can be done by adding it to "Other linker flags" in the build
 settings. For Bazel, this can be done with ``--linkopt`` or with
-[rules_apple_linker](https://github.com/keith/rules_apple_linker).
+`rules_apple_linker <https://github.com/keith/rules_apple_linker>`_.
 The user may also need to add ``-Wl,--deduplicate-literals`` in order
 to match Apple's linker behavior more closely (otherwise problems
-can occur, for instance, in unit tests). For more info on
-the differences between the two, see "LD64 vs LLD-MACHO", mentioned below.
+can occur, for instance, in unit tests).
+
+.. seealso::
+
+  :doc:`ld64-vs-lld` has more info on the differences between the two linkers.
 
 .. toctree::
-   :maxdepth: 1
+   :hidden:
 
    ld64-vs-lld

lld/docs/MachO/ld64-vs-lld.rst

-==================
-LD64 vs LLD-MACHO
-==================
+=================
+ld64 vs LLD-MachO
+=================
 
-This doc lists all significant deliberate differences in behavior between LD64 and LLD-MachO.
+This doc lists all significant deliberate differences in behavior between ld64
+and LLD-MachO.
 
 String Literal Deduplication
 ****************************
-LD64 always deduplicates string literals. LLD only does it when the ``--icf=``
+ld64 always deduplicates string literals. LLD only does it when the ``--icf=``
 or the ``--deduplicate-literals`` flag is passed. Omitting deduplication by
 default ensures that our link is as fast as possible. However, it may also break
 some programs which have (incorrectly) relied on string deduplication always
 occurring. In particular, programs which compare string literals via pointer
 equality must be fixed to use value equality instead.
 
-String Alignment
-****************
-LLD is slightly less conservative about aligning cstrings, allowing it to pack
-them more compactly. This should not result in any meaningful semantic
-difference.
-
 ``-no_deduplicate`` Flag
 ************************
-- LD64:
-   * This turns off ICF (deduplication pass) in the linker.
-- LLD
-   * This turns off ICF and string merging in the linker.
+- ld64: This turns off ICF (deduplication pass) in the linker.
+- LLD: This turns off ICF and string merging in the linker.
+
+String Alignment
+****************
+LLD is `slightly less conservative about aligning cstrings
+<https://reviews.llvm.org/D121342>`_, allowing it to pack them more compactly.
+This should not result in any meaningful semantic difference.
 
 ObjC Symbols Treatment
 **********************
-There are differences in how LLD and LD64 handle ObjC symbols loaded from archives.
+There are differences in how LLD and ld64 handle ObjC symbols loaded from
+archives.
 
-- LD64:
-   * Duplicate ObjC symbols from the same archives will not raise an error. LD64 will pick the first one.
-   * Duplicate ObjC symbols from different archives will raise a "duplicate symbol" error.
-- LLD:
-   * Duplicate symbols, regardless of which archives they are from, will raise errors.
+- ld64:
+   1. Duplicate ObjC symbols from the same archives will not raise an error.
+      ld64 will pick the first one.
+   2. Duplicate ObjC symbols from different archives will raise a "duplicate
+      symbol" error.
+- LLD: Duplicate symbols, regardless of which archives they are from, will
+  raise errors.