docs: fix accumulator example in stats/incr/nanpcorr2

Follow-up to 6570c4f. The `@example` block in main.js and the identical examples in docs/types/index.d.ts and docs/repl.txt only supplied one valid `(x, y)` pair followed by four NaN-poisoned calls, so the correlation never accumulated a second data point and the result stayed at 0.0 for every follow-up call — failing to demonstrate that NaN inputs are ignored. Interleave a second valid pair `accumulator( 1.0, 90.0 )` (mirroring the README) so subsequent NaN calls correctly show `~1.0`.

Author: claude

lib/node_modules/@stdlib/stats/incr/nanpcorr2/docs/repl.txt

@@ -27,14 +27,16 @@
     null
     > r2 = accumulator( 2.0, 1.0 )
     0.0
+    > r2 = accumulator( 1.0, 90.0 )
+    1.0
     > r2 = accumulator( -5.0, NaN )
-    ~0.0
+    ~1.0
     > r2 = accumulator( NaN, NaN )
-    ~0.0
+    ~1.0
     > r2 = accumulator( NaN, -8.0 )
-    ~0.0
+    ~1.0
     > r2 = accumulator()
-    ~0.0
+    ~1.0
 
     See Also
     --------

lib/node_modules/@stdlib/stats/incr/nanpcorr2/docs/types/index.d.ts

@@ -55,17 +55,20 @@ declare function incrnanpcorr2( meanx: number, meany: number ): accumulator;
 * r2 = accumulator( 2.0, 1.0 );
 * // returns 0.0
 *
+* r2 = accumulator( 1.0, 90.0 );
+* // returns 1.0
+*
 * r2 = accumulator( -5.0, NaN );
-* // returns ~0.0
+* // returns ~1.0
 *
 * r2 = accumulator( NaN, NaN );
-* // returns ~0.0
+* // returns ~1.0
 *
 * r2 = accumulator( NaN, 8.0 );
-* // returns ~0.0
+* // returns ~1.0
 *
 * r2 = accumulator();
-* // returns ~0.0
+* // returns ~1.0
 */
 declare function incrnanpcorr2(): accumulator;
 

lib/node_modules/@stdlib/stats/incr/nanpcorr2/lib/main.js

@@ -44,17 +44,20 @@ var incrpcorr2 = require( '@stdlib/stats/incr/pcorr2' );
 * r2 = accumulator( 2.0, 1.0 );
 * // returns 0.0
 *
+* r2 = accumulator( 1.0, 90.0 );
+* // returns 1.0
+*
 * r2 = accumulator( -5.0, NaN );
-* // returns ~0.0
+* // returns ~1.0
 *
 * r2 = accumulator( NaN, NaN );
-* // returns ~0.0
+* // returns ~1.0
 *
 * r2 = accumulator( NaN, 8.0 );
-* // returns ~0.0
+* // returns ~1.0
 *
 * r2 = accumulator();
-* // returns ~0.0
+* // returns ~1.0
 *
 * @example
 * var accumulator = incrnanpcorr2( 2.0, -3.0 );