Make a bit clearer

Author: lucs

doc/Type/Grammar.pod6

@@ -55,8 +55,8 @@ sole positional argument.
     grammar { token TOP { a { say "42" } b } }.parse('ab', :$actions);
     # OUTPUT : «42␤7␤»
 
-Additional named arguments are used as options for matching, so you can specify
-things like C<:pos(4)> to start parsing from the fourth (zero-base) character.
+Additional named arguments are used as options for matching, so you can for example specify
+things like C<:pos(4)> to start parsing from the fifth (:pos is zero-based) character.
 All L<matching adverbs|/language/regexes#Adverbs> are allowed, but not all of
 them take effect. There are several types of adverbs that a regex can have,
 some of which apply at compile time, like C<:s> and C<:i>. You cannot pass those