Big cleanup in config help and description

Redundant help texts (one which only repeats the description)
are deleted.

Descriptions and help texts are trimmed.

Some config options are moved, even across menus.

No config option _names_ are changed.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/df.c b/coreutils/df.c
index 79e4c46..cf36716 100644
--- a/coreutils/df.c
+++ b/coreutils/df.c
@@ -29,11 +29,9 @@
 //config:	default y
 //config:	depends on DF
 //config:	help
-//config:	  This option enables -a, -i and -B.
-//config:
-//config:	    -a Show all filesystems
-//config:	    -i Inodes
-//config:	    -B <SIZE> Blocksize
+//config:	  -a Show all filesystems
+//config:	  -i Inodes
+//config:	  -B <SIZE> Blocksize
 
 //applet:IF_DF(APPLET(df, BB_DIR_BIN, BB_SUID_DROP))