docs: update comment

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

Author: kgryte

lib/node_modules/@stdlib/blas/ext/base/ddiff/examples/c/example.c

@@ -32,7 +32,7 @@ int main( void ) {
 	// Define the output array:
 	double out[] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 };
 
-	// Define the workspace:
+	// Define a workspace:
 	double w[] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 };
 
 	// Compute forward differences: