docs: remove outdated config option from readme (#1543)

README.md

@@ -253,7 +253,6 @@ You can use all of the following options with standalone version on <redoc> tag
   * **function**: A getter function. Must return a number representing the offset (in pixels).
 * `showExtensions` - show vendor extensions ("x-" fields). Extensions used by ReDoc are ignored. Can be boolean or an array of `string` with names of extensions to display.
 * `sortPropsAlphabetically` - sort properties alphabetically.
-* `suppressWarnings` - if set, warnings are not rendered at the top of documentation (they still are logged to the console).
 * `payloadSampleIdx` - if set, payload sample will be inserted at this index or last. Indexes start from 0.
 * `theme` - ReDoc theme. For details check [theme docs](#redoc-theme-object).
 * `untrustedSpec` - if set, the spec is considered untrusted and all HTML/markdown is sanitized to prevent XSS. **Disabled by default** for performance reasons. **Enable this option if you work with untrusted user data!**