sha256 hash returns incorrect result if input's `(byteLength & 63) == 63`

The hash function returns incorrect result for any inputs where `byteLength % 64 == 63`. To reproduce create a test case where byte length % 64 == 63 and compare it against another implementation of sha256.

**example test one:**
```ts
it("hex bytes of 191 byte length", function () {
const inputStr = "1".repeat(382);
const input = Buffer.from(inputStr, "hex");
expect(input.length).to.be.equal(191);

const output = Buffer.from(sha256.digest(input)).toString("hex");
expect(output).to.be.equal("b8ffd888fe6ffff63cb0193ad93b0fee6bda8ea913e4e75424af7914f55d3411");
});
```
**example one output running `yarn test`**

```bash
AssertionError: expected 'de66d39d769de0b512fe724191d53339a3efc…' to equal 'b8ffd888fe6ffff63cb0193ad93b0fee6bda8…'
+ expected - actual

-de66d39d769de0b512fe724191d53339a3efc491875c25795a2c20bb7c03ad32
+b8ffd888fe6ffff63cb0193ad93b0fee6bda8ea913e4e75424af7914f55d3411
```
**example two**
```js
it("hex bytes of 676 byte length", function () {
const inputStr = "1".repeat(1150);
const input = Buffer.from(inputStr, "hex");
expect(input.length).to.be.equal(575);

const output = Buffer.from(sha256.digest(input)).toString("hex");
expect(output).to.be.equal("fc6b0073005a8ce2b4bf9a9c482bb2b1707bc1dab06c0185752104157edb62c6");
});
```
**example two output running `yarn test`**
```bash
digest function
hex bytes of 575 byte length:

AssertionError: expected '758a6d0187dfd01483d6a7e742bdda25a2f47…' to equal 'fc6b0073005a8ce2b4bf9a9c482bb2b1707bc…'
+ expected - actual

-758a6d0187dfd01483d6a7e742bdda25a2f47ef804fed45423484b27a6717243
+fc6b0073005a8ce2b4bf9a9c482bb2b1707bc1dab06c0185752104157edb62c6

at Context. (test/unit/index.test.ts:22:28)
at processImmediate (node:internal/timers:478:21)
```
I am still working through why this behavior occurs - I believe this could be an edge case in the math that is not handled correctly, any assistance on this would be greatly appreciated.