docs: change variable naming in blas/base/zaxpy

Signed-off-by: Shabareesh Shetty <[email protected]>

Author: ShabiShett07

lib/node_modules/@stdlib/blas/base/zcopy/benchmark/fortran/benchmark.length.f

@@ -117,8 +117,8 @@ double precision function benchmark( iterations, len )
     ! ..
     ! External functions:
     interface
-      subroutine zcopy( N, zx, strideX, zy, strideY )
-        complex(kind=kind(0.0d0)) :: zx(*), zy(*)
+      subroutine zcopy( N, x, strideX, y, strideY )
+        complex(kind=kind(0.0d0)) :: x(*), y(*)
         integer :: strideX, strideY, N
       end subroutine zcopy
     end interface
@@ -207,4 +207,4 @@ subroutine main()
     end do
     call print_summary( count, count )
   end subroutine main
-end program bench
+end program bench