Use a coherent wording for look-{ahead|around}.

Remove the dash in occurences so that it is spelled as either lookaround or
lookbehind. This seems a little more coherent with the terminology used also
in Perl 5 (perldoc perlre).

Author: fluca1978

doc/Language/5to6-nutshell.pod6

@@ -1106,7 +1106,7 @@ For character classes, this means that:
 
 =item C<[abc[:upper:]]> becomes C«<[abc]+:Upper>»
 
-For look-around assertions:
+For lookaround assertions:
 
 =item C<(?=[abc])> becomes C«<?[abc]>»
 

doc/Language/regexes.pod6

@@ -571,8 +571,8 @@ This can be useful for augmenting an existing regex. For example if you have
 a regex C<quoted> that matches a quoted string, then C</ <quoted> && <-[x]>* />
 matches a quoted string that does not contain the character C<x>.
 
-Note that you cannot easily obtain the same behavior with a look-ahead, that
-is, a regex doesn't consume characters, because a look-ahead doesn't stop
+Note that you cannot easily obtain the same behavior with a lookahead, that
+is, a regex doesn't consume characters, because a lookahead doesn't stop
 looking when the quoted string stops matching.
 
     =begin code
@@ -772,7 +772,7 @@ match with
     say "foobar" ~~ rx{ foo <!before bar> }   # OUTPUT: «Nil␤»
 
 
-Look-around assertions can be used also with other patterns, like
+lookahead assertions can be used also with other patterns, like
 characters ranges, interpolated variables, subscripts and so on. In such
 cases it does suffice to use a C<?> (or a C<!> for the negate form) immeditely
 followed by the character classes, interpolated variable and more in general