INCRBYFLOATIncrement the float value of a key by the given amount.
| 语法 | INCRBYFLOAT key increment |
| 分组 | string |
| 参数个数 | 3 |
| 起始版本 | 1.0.0 |
| 标志 | write |
| 复杂度 | O(1) |
| Redis 兼容性 | differs: arithmetic is f64 and the reply uses Rust's shortest-round-trip float printer, not a long double accumulator, so trailing digits can diverge from Redis |