docs: remove redundant copy

Signed-off-by: Athan <kgryte@gmail.com>

Author: kgryte

lib/node_modules/@stdlib/blas/ext/base/drssbl/README.md

@@ -102,8 +102,6 @@ var z = drssbl( 4, x1, 2, y1, 2 );
 // returns 50.0
 ```
 
-If `N` is less than or equal to `0`, the function returns `0`.
-
 #### drssbl.ndarray( N, x, strideX, offsetX,  y, strideY, offsetY )
 
 Computes the [residual sum of squares][wikipedia-residual-sum-of-squares] of two double-precision floating-point strided arrays using Blue's algorithm and alternative indexing semantics.