A few docs clarifications.

-- shifted mappings notation (<C-n> vs <C-N>)
-- adjusted the ':!' warning
-- other minor fixes

vimperator/locale/en-US/styling.txt

@@ -18,11 +18,11 @@ sourced.
 ________________________________________________________________________________
 
 |:hi| |:highlight| +
-||:hi[ghlight][!] [-append] {group}[{selector}] [{css}]|| +
+||:hi[ghlight][!] [-append] {group} [[{selector}] {css}]|| +
 ________________________________________________________________________________
 Highlight {group} with {css}. Normally, {css} is checked for valid
 syntax before it's applied. Once you're certain it's valid, [!] can be
-used to override the check to speed Vimperator startup. {selector} can
+used to skip the check to speed up Vimperator startup. {selector} can
 be any valid CSS selector, such as [c]:hover[c], and, if provided, will
 restrict the match to matching elements.
 
@@ -89,11 +89,11 @@ Valid groups are:
 Every invocation completely replaces the styling of any previous invocation,
 unless *-append* (short option: *-a*) is provided, in which case {css} is
 appended to its current value. If {css} is not provided, any styles matching
-{group} are listed.
+{group} are listed, or all styles if no {group} provided.
 ________________________________________________________________________________
 
 |:highlight-clear| +
-||:hi[light] clear [{group}[{selector}]]|| +
+||:hi[ghlight] clear [{group} [{selector}]]|| +
 ________________________________________________________________________________
 Reset the highlighting for {group} to its default value. If
 {group} is not given, reset all highlighting groups.