fix: Apply suggestions from code review

Signed-off-by: Vinit Pandit <[email protected]>

Author: Vinit-Pandit

lib/node_modules/@stdlib/stats/base/dists/rayleigh/entropy/README.md

@@ -195,7 +195,7 @@ int main( void ) {
     for ( i = 0; i < 25; i++ ) {
         sigma = random_uniform( 0.0, 20.0 );
         y = stdlib_base_dists_rayleigh_entropy( sigma );
-        printf( "σ: %lf, h(x;σ): %lf\n", sigma, y );
+        printf( "σ: %lf, h(σ): %lf\n", sigma, y );
     }
 }
 ```

lib/node_modules/@stdlib/stats/base/dists/rayleigh/entropy/examples/c/example.c

@@ -33,6 +33,6 @@ int main( void ) {
 	for ( i = 0; i < 25; i++ ) {
 		sigma = random_uniform( 0.0, 20.0 );
 		y = stdlib_base_dists_rayleigh_entropy( sigma );
-		printf( "σ: %lf, h(x;σ): %lf\n", sigma, y );
+		printf( "σ: %lf, h(σ): %lf\n", sigma, y );
 	}
 }

lib/node_modules/@stdlib/stats/base/dists/rayleigh/entropy/src/main.c

@@ -34,7 +34,6 @@
 * // returns ~3.139
 */
 double stdlib_base_dists_rayleigh_entropy( const double sigma ) {
-	double s2;
 	if (
 		stdlib_base_is_nan( sigma ) ||
 		sigma <= 0.0