refactor: remove include and fix return type

PR-URL: stdlib-js#2699
Ref: stdlib-js@f5d15f7#r144735243
Ref: stdlib-js@f5d15f7#r144735169
Reviewed-by: Athan Reines <[email protected]>

Author: gunjjoshi

lib/node_modules/@stdlib/math/base/special/sincospi/lib/native.js

@@ -31,7 +31,7 @@ var addon = require( './../src/addon.node' );
 *
 * @private
 * @param {number} x - input value
-* @returns {Array<number>} two-element array containing sin(πx) and cos(πx)
+* @returns {Float64Array} two-element array containing sin(πx) and cos(πx)
 *
 * @example
 * var v = sincospi( 0.0 );

lib/node_modules/@stdlib/math/base/special/sincospi/src/main.c

@@ -25,7 +25,6 @@
 #include "stdlib/math/base/assert/is_infinite.h"
 #include "stdlib/math/base/assert/is_nan.h"
 #include "stdlib/constants/float64/pi.h"
-#include <stdint.h>
 
 /**
 * Simultaneously computes the sine and cosine of a number times π.