Updated comments

regex/matching.go

@@ -6,11 +6,12 @@ import (
 )
 
 // A Match represents a match found by the regex in a given string.
-// It is represented as a list of [Group]s, where the nth element contains
-// the indices matched by the nth capturing group. The element at index 0 is known
+// It is represented as a list of groups, where the nth element contains
+// the contents of the nth capturing group. Note that the group may not be valid
+// (see [Group.IsValid]). The element at index 0 is known
 // as the 0-group, and represents the contents of the entire match.
 //
-// See [Regex.FindSubmatch] for an example.
+// See [Reg.FindSubmatch] for an example.
 type Match []Group
 
 // a Group represents a group. It contains the start index and end index of the match