update specs for median

Author: jvdp1

doc/specs/stdlib_stats.md

@@ -204,9 +204,9 @@ and if `n` is an odd number, the median is:
 median(array) = mean( array_sorted( floor( (n + 1) / 2.):floor( (n + 1) / 2.) + 1 ) )
 ```
 
-The current implementation is a quite naive implementation that relies on sorting
-the whole array, using the subroutine `[[stdlib_sorting(module):ord_sort(interface)]]`
-provided by the `[[stdlib_sorting(module)]]` module.
+The current implementation relies on a selection algorithm applied on a copy of
+the whole array, using the subroutine `[[stdlib_selection(module):select(interface)]]`
+provided by the `[[stdlib_selection(module)]]` module.
 
 ### Syntax
 
@@ -220,11 +220,12 @@ Generic subroutine
 
 ### Arguments
 
-`array`: Shall be an array of type `integer` or `real`.
+`array`: Shall be an array of type `integer` or `real`. It is an `intent(in)`
+argument.
 
-`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`.
+`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`. It is an `intent(in)` argument.
 
-`mask` (optional): Shall be of type `logical` and either a scalar or an array of the same shape as `array`.
+`mask` (optional): Shall be of type `logical` and either a scalar or an array of the same shape as `array`. It is an `intent(in)` argument.
 
 ### Return value