docs: fix typo in api.mdx (#1477)

Author: fetsorn

docs/solid-testing-library/api.mdx

@@ -15,7 +15,7 @@ There are several key differences, to be aware of.
 - [`renderHook`](#renderHook)
 - [`renderDirective`](#renderDirective)
 - [`Async methods`](#async-methods)
-- [`Know issues`](#known-issues)
+- [`Known issues`](#known-issues)
 
 ## `render`