docs: remove unused definition

Signed-off-by: Athan <[email protected]>

Author: kgryte

lib/node_modules/@stdlib/stats/strided/covarmtk/README.md

@@ -243,8 +243,6 @@ console.log( v );
 
 [covariance]: https://en.wikipedia.org/wiki/Covariance
 
-[@stdlib/array/float64]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/float64
-
 [mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
 
 [mdn-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array