docs: clarify description of the offset option

Author: LennartSpitzner

README.md

@@ -80,7 +80,7 @@ Notes:
 | eventOff         | data-event-off        | String        | e.g. click                                                                                                                            | custom event to hide tooltip (only makes effect after setting event attribute)                                                                                                                      |
 | globalEventOff   |                       | String        | e.g. click                                                                                                                            | global event to hide tooltip (global only)                                                                                                                                                          |
 | isCapture        | data-iscapture        | Bool          | true, false                                                                                                                           | when set to true, custom event's propagation mode will be capture                                                                                                                                   |
-| offset           | data-offset           | Object        | top, right, bottom, left                                                                                                              | `data-offset="{'top': 10, 'left': 10}"` for specific and `offset={{top: 10, left: 10}}` for global                                                                                                  |
+| offset           | data-offset           | Object        | { top?: number, right?: number, bottom?: number, left?: number }                                                                      | `data-offset="{'top': 10, 'left': 10}"` for specific and `offset={{top: 10, left: 10}}` for global                                                                                                  |
 | padding          | data-padding          | String        | e.g. `8px 21px`                                                                                                                       | Popup padding style                                                                                                                                                                                 |
 | multiline        | data-multiline        | Bool          | true, false                                                                                                                           | support `<br>`, `<br />` to make multiline                                                                                                                                                          |
 | className        | data-class            | String        |                                                                                                                                       | extra custom class, can use !important to overwrite react-tooltip's default class                                                                                                                   |