tests: Fix the test added in the last commit.

highlighters/main/test-data/backslash-continuation2.zsh

@@ -32,6 +32,6 @@ BUFFER=$'echo foo\\\nbar"baz"'
 
 expected_region_highlight=(
   '1 4 builtin' # echo
-  '6 18 default' # foo\\\nbar"baz"
+  '6 18 default "issue #705"' # foo\\\nbar"baz"
   '14 18 double-quoted-argument "issue #705"' # "baz"
 )