Show missing backslash in manual (#2492)

docs/content/manual/v1.6/manual.yml

@@ -2361,7 +2361,7 @@ sections:
           be a jq string, and may contain references to named captures. The
           named captures are, in effect, presented as a JSON object (as
           constructed by `capture`) to `tostring`, so a reference to a captured
-          variable named "x" would take the form: "\(.x)".
+          variable named "x" would take the form: `"\(.x)"`.
 
         example:
           - program: 'sub("^[^a-z]*(?<x>[a-z]*).*")'