Documentation/llvm: Improve formatting of commands, variables, and arguments

While reviewing a separate patch, I noticed that the formatting of the
commands, variables, and arguments was not in a monospaced font like the
rest of the Kbuild documentation (see kbuild/kconfig.rst for an
example). This is due to a lack of "::" before indented command blocks
and single backticks instead of double backticks for inline formatting.

Add those so that the document looks nicer in an HTML format, while not
ruining the look in plain text.

As a result of this, we can remove the escaped backslashes in the last
code block and move them to single backslashes.
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Documentation/kbuild/llvm.rst

@@ -23,8 +23,8 @@ supports C and the GNU C extensions required by the kernel, and is pronounced
 Clang
 -----
 
-The compiler used can be swapped out via `CC=` command line argument to `make`.
-`CC=` should be set when selecting a config and during a build.
+The compiler used can be swapped out via ``CC=`` command line argument to ``make``.
+``CC=`` should be set when selecting a config and during a build. ::
 
 	make CC=clang defconfig
 
@@ -34,33 +34,33 @@ Cross Compiling
 ---------------
 
 A single Clang compiler binary will typically contain all supported backends,
-which can help simplify cross compiling.
+which can help simplify cross compiling. ::
 
 	ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make CC=clang
 
-`CROSS_COMPILE` is not used to prefix the Clang compiler binary, instead
-`CROSS_COMPILE` is used to set a command line flag: `--target <triple>`. For
-example:
+``CROSS_COMPILE`` is not used to prefix the Clang compiler binary, instead
+``CROSS_COMPILE`` is used to set a command line flag: ``--target <triple>``. For
+example: ::
 
 	clang --target aarch64-linux-gnu foo.c
 
 LLVM Utilities
 --------------
 
-LLVM has substitutes for GNU binutils utilities. Kbuild supports `LLVM=1`
-to enable them.
+LLVM has substitutes for GNU binutils utilities. Kbuild supports ``LLVM=1``
+to enable them. ::
 
 	make LLVM=1
 
-They can be enabled individually. The full list of the parameters:
+They can be enabled individually. The full list of the parameters: ::
 
-	make CC=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip \\
-	  OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump OBJSIZE=llvm-size \\
-	  READELF=llvm-readelf HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar \\
+	make CC=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip \
+	  OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump OBJSIZE=llvm-size \
+	  READELF=llvm-readelf HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar \
 	  HOSTLD=ld.lld
 
 Currently, the integrated assembler is disabled by default. You can pass
-`LLVM_IAS=1` to enable it.
+``LLVM_IAS=1`` to enable it.
 
 Getting Help
 ------------