Update index.d.ts

Signed-off-by: Gururaj Gurram <143020143+gururaj1512@users.noreply.github.com>

Author: gururaj1512

lib/node_modules/@stdlib/stats/base/ndarray/dcovarmtk/docs/types/index.d.ts

@@ -36,7 +36,7 @@ import { float64ndarray } from '@stdlib/types/ndarray';
 *     -   a zero-dimensional ndarray specifying degrees of freedom adjustment. Setting this parameter to a value other than `0` has the effect of adjusting the divisor during the calculation of the covariance according to `N-c` where `c` corresponds to the provided degrees of freedom adjustment. When computing the population covariance, setting this parameter to `0` is the standard choice (i.e., the provided arrays contain data constituting entire populations). When computing the unbiased sample covariance, setting this parameter to `1` is the standard choice (i.e., the provided arrays contain data sampled from larger populations; this is commonly referred to as Bessel's correction).
 *
 * @param arrays - array-like object containing input ndarrays
-* @returns maximum value
+* @returns covariance
 *
 * @example
 * var Float64Array = require( '@stdlib/array/float64' );