Fix some typos.

Make the paragraph short, it should be clear enough.

Author: fluca1978

doc/Language/regexes.pod6

@@ -772,12 +772,10 @@ match with
     say "foobar" ~~ rx{ foo <!before bar> }   # OUTPUT: «Nil␤»
 
 
-lookahead 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
-the "thing" to match against. For instance, the following lines
-all produce the very same result:
+cases it does suffice to use a C<?> (or a C<!> for the negate form).
+For instance, the following lines all produce the very same result:
 
 =begin code
 say 'abcdefg' ~~ rx{ abc <?before def> };        # OUTPUT: ｢abc｣