fix: use correct mathematical notation ln(f(x;k)) in C example

Changed printf format from 'logf(x;k)' to 'ln(f(x;k))' to match
standard mathematical notation for natural logarithm of PDF.

Author: Planeshifter

lib/node_modules/@stdlib/stats/base/dists/chi/logpdf/examples/c/example.c

@@ -35,7 +35,7 @@ int main( void ) {
 		x = random_uniform( 0.0, 10.0 );
 		k = random_uniform( 0.1, 10.0 );
 		y = stdlib_base_dists_chi_logpdf( x, k );
-		printf( "x: %lf, k: %lf, logf(x;k): %lf\n", x, k, y );
+		printf( "x: %lf, k: %lf, ln(f(x;k)): %lf\n", x, k, y );
 	}
 	return 0;
 }