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/split.c b/coreutils/split.c
index 50918a1..7af359d 100644
--- a/coreutils/split.c
+++ b/coreutils/split.c
@@ -9,7 +9,7 @@
 //config:	bool "split"
 //config:	default y
 //config:	help
-//config:	  split a file into pieces.
+//config:	  Split a file into pieces.
 //config:
 //config:config FEATURE_SPLIT_FANCY
 //config:	bool "Fancy extensions"