Update src/nf/nf_layer_constructors.f90

Co-authored-by: Jeremie Vandenplas <jeremie.vandenplas@gmail.com>

Author: milancurcic

src/nf/nf_layer_constructors.f90

@@ -107,7 +107,7 @@ module function conv1d(filters, kernel_width, activation) result(res)
       !! Example:
       !!
       !! ```
-      !! use nf, only :: conv1d, layer
+      !! use nf, only :: conv, layer
       !! type(layer) :: conv1d_layer
       !! conv1d_layer = conv1d(filters=32, kernel_size=3)
       !! ```