Update README.md

Signed-off-by: Rutam <[email protected]>

lib/node_modules/@stdlib/math/base/assert/is-composite/README.md

@@ -111,6 +111,8 @@ bool = isComposite( NaN );
 Tests if a finite double-precision floating-point number is a composite number.
 
 ```c
+#include <stdbool.h>
+
 bool out = stdlib_base_is_composite( 3 );
 // returns false
 ```