Brace, not bracket.

Since the remaining issue in this file comes from rakudo itself,
skip the problem text explicitly and refer to the rakudo bug.

Author: coke

doc/Type/X/Syntax/Comment/Embedded.pod6

@@ -7,7 +7,7 @@
     class X::Syntax::Comment::Embedded does X::Syntax { }
 
 Syntax error thrown when C<#`> is encountered and it is not followed by
-an opening curly bracket.
+an opening curly brace.
 
 For example
 

xt/braces.t

@@ -22,7 +22,8 @@ sub test-it(Str $output, Str $file) {
 
     my $msg;
 
-    my $line = $output.subst(/\s+/, ' ', :g); # canonicalize whitespace
+    my $line = $output.subst(/\s+/, ' ', :g)                         # canonicalize whitespace
+                      .subst('Opening bracket is required for', ''); # rakudo/rakudo#2672
 
     if $line ~~ /:i <!after curly> ' ' 'braces' >> / {
         $msg ~= "Found 'braces' without 'curly'. ";