Fix for missing parenthesis in Summary

Flagged during PR review

Author: AdamBurtEtch

16/umbraco-cms/SUMMARY.md

@@ -82,7 +82,7 @@
         * [Block Level Variance](fundamentals/backoffice/property-editors/built-in-umbraco-property-editors/block-editor/block-level-variance.md)
       * [Dropdown](fundamentals/backoffice/property-editors/built-in-umbraco-property-editors/dropdown/README.md)
       * [Rich Text Editor](fundamentals/backoffice/property-editors/built-in-umbraco-property-editors/rich-text-editor/README.md)
-        * [Configuration](fundamentals/backoffice/property-editors/built-in-umbraco-property-editors/rich-text-editor/configuration.md
+        * [Configuration](fundamentals/backoffice/property-editors/built-in-umbraco-property-editors/rich-text-editor/configuration.md)
         * [Blocks](fundamentals/backoffice/property-editors/built-in-umbraco-property-editors/rich-text-editor/blocks.md)
         * [Custom CSS properties](fundamentals/backoffice/property-editors/built-in-umbraco-property-editors/rich-text-editor/css-properties.md)
         * [Extensions](fundamentals/backoffice/property-editors/built-in-umbraco-property-editors/rich-text-editor/extensions.md)