Help: MSVC now has C standard level flags

Help/prop_tgt/C_STANDARD.rst

@@ -8,8 +8,8 @@ The C standard whose features are requested to build this target.
 This property specifies the C standard whose features are requested
 to build this target.  For some compilers, this results in adding a
 flag such as ``-std=gnu11`` to the compile line.  For compilers that
-have no notion of a C standard level, such as all versions of
-MSVC known as of this version of CMake, this has no effect.
+have no notion of a C standard level, such as Microsoft Visual C++ before
+VS 16.7, this property has no effect.
 
 Supported values are ``90``, ``99`` and ``11``.
 

Help/prop_tgt/C_STANDARD_REQUIRED.rst

@@ -9,8 +9,8 @@ If this property is set to ``ON``, then the value of the
 :prop_tgt:`C_STANDARD` target property is treated as a requirement.  If this
 property is ``OFF`` or unset, the :prop_tgt:`C_STANDARD` target property is
 treated as optional and may "decay" to a previous standard if the requested is
-not available.  For compilers that have no notion of a standard level, such as
-MSVC 1800 (Visual Studio 2013) and lower, this has no effect.
+not available.  For compilers that have no notion of a C standard level, such
+as Microsoft Visual C++ before VS 16.7, this property has no effect.
 
 See the :manual:`cmake-compile-features(7)` manual for information on
 compile features and a list of supported compilers.