Fix table layout in regexes/regex interpolation section

doc/Language/regexes.pod6

@@ -1645,11 +1645,14 @@ pattern, which may be summarized as follows:
 
     Syntax         | Description
     ===============+===========================================================
-    C«$variable»   | Interpolates stringified contents of variable literally.
-    C«$(code)»     | Runs Perl 6 code inside the regex, and interpolates the
+    $variable      | Interpolates stringified contents of variable literally.
+    ---------------------------------------------------------------------------
+    $(code)        | Runs Perl 6 code inside the regex, and interpolates the
                    | stringified return value literally.
-    C«<$variable>» | Interpolates stringified contents of variable as a regex.
-    C«<{code}>»    | Runs Perl 6 code inside the regex, and interpolates the
+    ---------------------------------------------------------------------------
+    <$variable>    | Interpolates stringified contents of variable as a regex.
+    ---------------------------------------------------------------------------
+    <{code}>       | Runs Perl 6 code inside the regex, and interpolates the
                    | stringified return value as a regex.
 
 =end table