add doc

Author: HerrCai0907

clang-tools-extra/docs/clang-tidy/checks/bugprone/unintended-char-ostream-output.rst

@@ -27,7 +27,7 @@ intent, by default, it will cast to ``unsigned int`` for ``unsigned char`` and
   std::cout << static_cast<int>(v); // when v is signed char
 
 To avoid lengthy cast statements, add prefix ``+`` to the variable can also
-suppress warnings.
+suppress warnings because unary expression will promote the value to an ``int``.
 
 .. code-block:: c++
 

clang-tools-extra/docs/clang-tidy/checks/list.rst

@@ -158,7 +158,7 @@ Clang-Tidy Checks
    :doc:`bugprone-undelegated-constructor <bugprone/undelegated-constructor>`,
    :doc:`bugprone-unhandled-exception-at-new <bugprone/unhandled-exception-at-new>`,
    :doc:`bugprone-unhandled-self-assignment <bugprone/unhandled-self-assignment>`,
-   :doc:`bugprone-unintended-char-ostream-output <bugprone/unintended-char-ostream-output>`,
+   :doc:`bugprone-unintended-char-ostream-output <bugprone/unintended-char-ostream-output>`, "Yes"
    :doc:`bugprone-unique-ptr-array-mismatch <bugprone/unique-ptr-array-mismatch>`, "Yes"
    :doc:`bugprone-unsafe-functions <bugprone/unsafe-functions>`,
    :doc:`bugprone-unused-local-non-trivial-variable <bugprone/unused-local-non-trivial-variable>`,