variance_dev: update spec var

Author: jvdp1

src/stdlib_experimental_stats.md

@@ -69,15 +69,15 @@ The variance is defined as the best unbiased estimator and is computed as:
 
 ### Arguments
 
-`array`: Shall be an array of type `integer`, or `real`.
+`array`: Shall be an array of type `integer`, `real`, or `complex`.
 
 `dim`: Shall be a scalar of type `integer` with a value in the range from 1 to n, where n is the rank of `array`.
 
 `mask` (optional): Shall be of type `logical` and either by a scalar or an array of the same shape as `array`.
 
 ### Return value
 
-If `array` is of type `real`, the result is of the same type as `array`.
+If `array` is of type `real` or `complex`, the result is of the same type as `array`.
 If `array` is of type `integer`, the result is of type `double precision`.
 
 If `dim` is absent, a scalar with the variance of all elements in `array` is returned. Otherwise, an array of rank n-1, where n equals the rank of `array`, and a shape similar to that of `ar