Doc: fontWeight can be a number (#258)

Author: thierryc

docs/styling.md

@@ -77,7 +77,7 @@ Components use CSS styles + flexbox layout.
 | `fontFamily` | `string` | ✅ |
 | `fontSize` | `number` | ✅ |
 | `fontStyle` | `normal` | `italic` | ✅ |
-| `fontWeight` | `string` | ✅ |
+| `fontWeight` | `string` | `number` | ✅ |
 | `textDecorationLine` | `none` | `underline` | `double` | `line-through`  | ✅ |
 | `textShadowOffset` | `{ width: number, height: number }` | ⛔️ |
 | `textShadowRadius` | `number` | ⛔️ |