CodingStyle: Remove "Don't use C99-style comments"

Because Linus may still be reading source code on greenbar paper
instead of color terminals with code syntax highlighting and
appropriate font decorations.

Link: http://lkml.kernel.org/r/CA+55aFyQYJerovMsSoSKS7PessZBr4vNp-3QUUwhqk4A4_jcbg@mail.gmail.comSigned-off-by: Joe Perches <joe@perches.com>

Documentation/CodingStyle

@@ -474,9 +474,6 @@ When commenting the kernel API functions, please use the kernel-doc format.
 See the files Documentation/kernel-documentation.rst and scripts/kernel-doc
 for details.
 
-Linux style for comments is the C89 "/* ... */" style.
-Don't use C99-style "// ..." comments.
-
 The preferred style for long (multi-line) comments is:
 
 	/*