Function formatSignedInt

formatSignedInt(n: number, min_len?: number, fill_string?: string): string
Formats a number with an explicit sign prefix (+, -, or ± for zero).
Parameters
- n: number
  The number to format.
- Optionalmin_len: number
  Minimum length of the numeric part (pads absolute value).
- Optionalfill_string: string
  Padding string (default: ' ').
Returns string
The formatted string with sign prefix.
Example
```
formatSignedInt(42);        // "+42"
formatSignedInt(-5);        // "-5"
formatSignedInt(0);         // "±0"
formatSignedInt(5, 3, '0'); // "+005"
```
- Defined in src/string/format.ts:42