[docs] Update doc for C++20 Modules after dc4e85b

After
dc4e85b,
we need to update the examples in the documents.

This patch also fix some other places where is no longer relevant.

Author: ChuanqiXu9

clang/docs/StandardCPlusPlusModules.rst

@@ -143,7 +143,7 @@ Then we type:
 .. code-block:: console
 
   $ clang++ -std=c++20 Hello.cppm --precompile -o Hello.pcm
-  $ clang++ -std=c++20 use.cpp -fprebuilt-module-path=. Hello.pcm -o Hello.out
+  $ clang++ -std=c++20 use.cpp -fmodule-file=Hello=Hello.pcm Hello.pcm -o Hello.out
   $ ./Hello.out
   Hello World!
 
@@ -200,15 +200,15 @@ Then we are able to compile the example by the following command:
   $ clang++ -std=c++20 interface_part.cppm --precompile -o M-interface_part.pcm
   $ clang++ -std=c++20 impl_part.cppm --precompile -fprebuilt-module-path=. -o M-impl_part.pcm
   $ clang++ -std=c++20 M.cppm --precompile -fprebuilt-module-path=. -o M.pcm
-  $ clang++ -std=c++20 Impl.cpp -fmodule-file=M=M.pcm -c -o Impl.o
+  $ clang++ -std=c++20 Impl.cpp -fprebuilt-module-path=. -c -o Impl.o
 
   # Compiling the user
   $ clang++ -std=c++20 User.cpp -fprebuilt-module-path=. -c -o User.o
 
   # Compiling the module and linking it together
-  $ clang++ -std=c++20 M-interface_part.pcm -c -o M-interface_part.o
-  $ clang++ -std=c++20 M-impl_part.pcm -c -o M-impl_part.o
-  $ clang++ -std=c++20 M.pcm -c -o M.o
+  $ clang++ -std=c++20 M-interface_part.pcm -fprebuilt-module-path=. -c -o M-interface_part.o
+  $ clang++ -std=c++20 M-impl_part.pcm -fprebuilt-module-path=. -c -o M-impl_part.o
+  $ clang++ -std=c++20 M.pcm -fprebuilt-module-path=. -c -o M.o
   $ clang++ User.o M-interface_part.o  M-impl_part.o M.o Impl.o -o a.out
 
 We explain the options in the following sections.
@@ -218,7 +218,6 @@ How to enable standard C++ modules
 
 Currently, standard C++ modules are enabled automatically
 if the language standard is ``-std=c++20`` or newer.
-The ``-fmodules-ts`` option is deprecated and is planned to be removed.
 
 How to produce a BMI
 ~~~~~~~~~~~~~~~~~~~~