Add more examples to clang tidy checkers

[alexfh]

Thanks!

LG with a couple of nits.

docs/clang-tidy/checks/misc-inefficient-algorithm.rst

25

std::count

docs/clang-tidy/checks/misc-unused-parameters.rst

25

The example seems incomplete?

[alexfh]

Another couple of post-commit comments.

docs/clang-tidy/checks/misc-unused-parameters.rst

15

nit: two spaces before the comment.

docs/clang-tidy/checks/readability-uniqueptr-delete-release.rst

11

nit: I'd add a bit more context, namely the definition of P.

[sylvestre.ledru]

docs/clang-tidy/checks/misc-unused-parameters.rst

15

I believe it is the case ?
I stole this from the unit test test/clang-tidy/misc-unused-parameters.c

docs/clang-tidy/checks/readability-uniqueptr-delete-release.rst

11

done in r299961

[alexfh]

docs/clang-tidy/checks/misc-unused-parameters.rst

15

Indeed. But now we have -format-style= option to fix formatting after applying fixes ;). Since it's not on by default, it's fair to leave the example as is.

docs/clang-tidy/checks/llvm-namespace-comment.rst

 
 https://google.github.io/styleguide/cppguide.html#Namespaces
 
+.. code-block:: c++
+
+  namespace n1 {
+  void f();
+  }
+
+  // becomes
+
+  namespace n1 {
+  void f();
+  }  // namespace n1
+
+
 Options
 -------
 

docs/clang-tidy/checks/llvm-twine-local.rst

 
 Looks for local ``Twine`` variables which are prone to use after frees and
 should be generally avoided.
+
+.. code-block:: c++
+
+  static Twine Moo = Twine("bark") + "bah";
+
+  // becomes
+
+  static std::string Moo = (Twine("bark") + "bah").str();

docs/clang-tidy/checks/misc-inefficient-algorithm.rst

 Associative containers implements some of the algorithms as methods which
 should be preferred to the algorithms in the algorithm header. The methods
 can take advanatage of the order of the elements.
+
+.. code-block:: c++
+
+  std::set<int> s;
+  auto it = std::find(s.begin(), s.end(), 43);
+
+  // becomes
+
+  auto it = s.find(43);
+
+.. code-block:: c++
+
+  std::set<int> s;
+  auto c = count(s.begin(), s.end(), 43);
+
+  // becomes
+
+  auto c = s.count(43);

docs/clang-tidy/checks/misc-unused-parameters.rst

 
 Finds unused parameters and fixes them, so that `-Wunused-parameter` can be
 turned on.
+
+.. code-block:: c++
+
+  void a(int i) {}
+
+  // becomes
+
+  void a(int  /*i*/) {}
+
+
+.. code-block:: c++
+
+  static void staticFunctionA(int i);
+  static void staticFunctionA(int i) {}
+
+  // becomes
+
+  static void staticFunctionA()

docs/clang-tidy/checks/performance-type-promotion-in-math-fn.rst

 For example, warns on ``::sin(0.f)``, because this funciton's parameter is a
 double. You probably meant to call ``std::sin(0.f)`` (in C++), or ``sinf(0.f)``
 (in C).
+
+.. code-block:: c++
+
+  float a;
+  asin(a);
+
+  // becomes
+
+  float a;
+  std::asin(a);

docs/clang-tidy/checks/readability-redundant-string-init.rst

   // Initializing string with empty string literal is unnecessary.
   std::string a = "";
   std::string b("");
+
+  // becomes
+
+  std::string a;
+  std::string b;

docs/clang-tidy/checks/readability-uniqueptr-delete-release.rst

 
 Replace ``delete <unique_ptr>.release()`` with ``<unique_ptr> = nullptr``.
 The latter is shorter, simpler and does not require use of raw pointer APIs.
+
+.. code-block:: c++
+
+  delete P.release();
+
+  // becomes
+
+  P = nullptr;