Fix signature typo, can't have two invocants

coke · coke · commit b5437dc7620d · 2017-10-12T07:52:43.000-04:00
Found by running xt tests.
diff --git a/doc/Type/Signature.pod6 b/doc/Type/Signature.pod6
@@ -754,7 +754,7 @@ Whatever the Signature's return constraint is:
 
 =head2 method ACCEPTS
 
-    multi method ACCEPTS(Signature:D: Signature: $topic)
+    multi method ACCEPTS(Signature:D: Signature $topic)
     multi method ACCEPTS(Signature:D: Capture $topic)
     multi method ACCEPTS(Signature:D: Mu \topic)
 
