Function isNullish

isNullish(value: unknown): value is undefined | null
Checks if a value is null or undefined.
Parameters
- value: unknown
  The value to check.
Returns value is undefined | null
True if the value is null or undefined.
Example
```
isNullish(null);        // true
isNullish(undefined);   // true
isNullish("");          // false
```
- Defined in src/safety/utils.ts:198