chore: add exports header comment

Signed-off-by: Philipp Burckhardt <[email protected]>

Author: Planeshifter

lib/node_modules/@stdlib/stats/base/dists/triangular/mgf/lib/phi2.js

@@ -39,4 +39,7 @@ function phi2( x ) {
 	return ( 2.0 * ( expm1( x ) - x ) ) / ( x*x );
 }
 
+
+// EXPORTS //
+
 module.exports = phi2;