kconfig: document Kconfig source file comments

I saw this type of Kconfig construct on LKML:

config SYMBOOL
	#bool "prompt string"
	default y

and wondered what it does.  Then I wondered if '#' comments are
even documented.  They aren't, so add a little doc for that.

Ah, good.  kconfig says:
arch/x86/Kconfig:2942:warning: config symbol defined without type

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt
index 3534a84d206c..64e0775a62d4 100644
--- a/Documentation/kbuild/kconfig-language.txt
+++ b/Documentation/kbuild/kconfig-language.txt
@@ -430,6 +430,12 @@ This sets the config program's title bar if the config program chooses
 to use it. It should be placed at the top of the configuration, before any
 other statement.
 
+'#' Kconfig source file comment:
+
+An unquoted '#' character anywhere in a source file line indicates
+the beginning of a source file comment.  The remainder of that line
+is a comment.
+
 
 Kconfig hints
 -------------