Add missing close-backtick in docs

docs/content/3.manual/manual.yml

@@ -534,7 +534,7 @@ sections:
           dictionaries or hashes), as in: `{"a": 42, "b": 17}`.
 
           If the keys are "identifier-like", then the quotes can be left
-          off, as in `{a:42, b:17}.  Keys generated by expressions need
+          off, as in `{a:42, b:17}`.  Keys generated by expressions need
           to be parenthesized, e.g., `{("a"+"b"):59}`.
 
           The value can be any expression (although you may need to