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>

libbb/Config.src

@@ -70,24 +70,13 @@ config FEATURE_FAST_TOP
 	  but code size is slightly bigger.
 
 config FEATURE_ETC_NETWORKS
-	bool "Support for /etc/networks"
+	bool "Support /etc/networks"
 	default n
 	help
 	  Enable support for network names in /etc/networks. This is
 	  a rarely used feature which allows you to use names
 	  instead of IP/mask pairs in route command.
 
-config FEATURE_USE_TERMIOS
-	bool "Use termios to manipulate the screen"
-	default y
-	depends on MORE || TOP || POWERTOP
-	help
-	  This option allows utilities such as 'more' and 'top' to determine
-	  the size of the screen. If you leave this disabled, your utilities
-	  that display things on the screen will be especially primitive and
-	  will be unable to determine the current screen size, and will be
-	  unable to move the cursor.
-
 config FEATURE_EDITING
 	bool "Command line editing"
 	default y
@@ -147,15 +136,11 @@ config FEATURE_TAB_COMPLETION
 	bool "Tab completion"
 	default y
 	depends on FEATURE_EDITING
-	help
-	  Enable tab completion.
 
 config FEATURE_USERNAME_COMPLETION
 	bool "Username completion"
 	default y
 	depends on FEATURE_TAB_COMPLETION
-	help
-	  Enable username completion.
 
 config FEATURE_EDITING_FANCY_PROMPT
 	bool "Fancy shell prompts"