docs: Prefer 'check-clang' to 'clang-test'

[modocache]

Summary

r159483 changed the canonical name of the Clang test target from
'clang-test' to 'check-clang'. Although the old name is still a valid
alias, update the documentation to use the new, canonical target name.

docs/LibASTMatchersTutorial.rst

 
 .. code-block:: console
 
       cd ~/clang-llvm
       mkdir build && cd build
       cmake -G Ninja ../llvm -DLLVM_BUILD_TESTS=ON  # Enable tests; default is off.
       ninja
       ninja check       # Test LLVM only.
-      ninja clang-test  # Test Clang only.
+      ninja check-clang # Test Clang only.
       ninja install
 
 And we're live.
 
 All of the tests should pass, though there is a (very) small chance that
 you can catch LLVM and Clang out of sync. Running ``'git svn rebase'``
 in both the llvm and clang directories should fix any problems.
 

www/hacking.html

<div id="content">
 
   <p>Clang includes a basic regression suite in the tree which can be
   run with <tt>make test</tt> from the top-level clang directory, or
   just <tt>make</tt> in the <em>test</em> sub-directory.
   <tt>make VERBOSE=1</tt> can be used to show more detail
   about what is being run.</p>
 
   <p>If you built LLVM and Clang using CMake, the test suite can be run
-  with <tt>make clang-test</tt> from the top-level LLVM directory.</p>
+  with <tt>make check-clang</tt> from the top-level LLVM directory.</p>
 
   <p>The tests primarily consist of a test runner script running the compiler
   under test on individual test files grouped in the directories under the
   test directory.  The individual test files include comments at the
   beginning indicating the Clang compile options to use, to be read
   by the test runner. Embedded comments also can do things like telling
   the test runner that an error is expected at the current line.
   Any output files produced by the test will be placed under