Move variable declaration before its use for Sass

In Sass, variable must be declared before it is used.
This also removes Miscellaneous section, because horizontal line color
and form / list paddings are Typography.

less/variables.less

@@ -822,6 +822,8 @@
 //
 //##
 
+//** Horizontal offset for forms and lists.
+@component-offset-horizontal: 180px;
 //** Text muted color
 @text-muted:                  @gray-light;
 //** Abbreviations and acronyms border color
@@ -838,14 +840,7 @@
 @page-header-border-color:    @gray-lighter;
 //** Width of horizontal description list titles
 @dl-horizontal-offset:        @component-offset-horizontal;
-
-
-//== Miscellaneous
-//
-//##
-
 //** Horizontal line color.
 @hr-border:                   @gray-lighter;
 
-//** Horizontal offset for forms and lists.
-@component-offset-horizontal: 180px;
+