update directionalCombo docs to mention :both

README.md

@@ -496,7 +496,7 @@ field type | `key` | `keys` | description | example
 `text`, `number`, `email`, `url`, `tel` | :heavy_check_mark: | optional | Optionally, these fields can match multiple tag `keys` of an OSM object: which is useful to support OSM tags which have more than one established tag key like `phone` and `contact:phone`.[^1] | `"key": "phone", "keys": ["phone", "contact:phone"]`
 `address` | :heavy_check_mark: | :heavy_check_mark: | `keys` must contains all possible subtags to be used in the address field and `key` must contain the tag key prefix (e.g. `addr`). | `"key": "addr", "keys": ["addr:city", "addr:street", …]`
 `wikipedia`, `wikidata` | :heavy_check_mark: | :heavy_check_mark: | As the values of these two fields should be updated in sync by the editor, the `keys` should always contain both the respective wikipedia and wikidata keys. | `"key": "flag:wikidata", "keys": ["flag:wikidata", "flag:wikipedia"]`
-`directionalCombo` | :heavy_check_mark: | :heavy_check_mark: | For directional fields, the `key` is the tag to use when the OSM feature has the same attributes in both directions, while the `keys` are the two tags for the individual directions. | `"key": "cycleway", "keys": ["cycleway:right", "cycleway:left"]`
+`directionalCombo` | :heavy_check_mark: | :heavy_check_mark: | For directional fields, the `key` is the tag to use when the OSM feature has the same attributes in both directions, while the `keys` are the two tags for the individual directions. iD considers `key` with and without the `:both` suffix (for example, `cycleway` and `cycleway:both`). | `"key": "cycleway", "keys": ["cycleway:right", "cycleway:left"]`
 `access` | :x: | :heavy_check_mark: | `keys` lists all access tags to consider in the field. | `"keys": ["access", "foot", "bicycle",  …]`
 `localized` | :heavy_check_mark: | :x: | `key` specified the main tag, which will also be used as the tag key prefix for localized versions of the tag (i.e. the `name` field will also display contents of the tags `name:*`). | `"key": "name"`
 `multiCombo` | :heavy_check_mark: | :x: | This field allows to toggle multiple `yes/no` subtags which share a common tag prefix specified in the field's `key`. | `"key": "recycling:"`