Update developers-guide.md

Author: AaronSadlerUK

docs/developers-guide.md

@@ -83,7 +83,7 @@ The **Doc Type Grid Editor** supports 3 config options, all of which are optiona
 
 | Member          | Type     | Description |
 |-----------------|----------|-------------|
-| AllowedDocTypes | String[] | An array of doc type aliases of which should be allowed to be selected in the grid editor. Strings can be REGEX patterns to allow matching groups of doc types in a single entry. e.g. "Widget$" will match all doc types with an alias ending in "Widget". However if a single doc type is matched, (aka **Single Doc Type Mode**), then doc type selection stage (in the DTGE panel) will be skipped. Note, your document type must be an Element type, in order to be usable in DTGE. |
+| AllowedDocTypes | String[] | An array of doc type aliases of which should be allowed to be selected in the grid editor. By default Strings are REGEX patterns to allow matching groups of doc types in a single entry. e.g. "widgetAlias" will match all doc types with an alias starting in "widgetAlias". By adding "$" to the end of the string you stop this behaviour e.g. "widgetAlias$" will only match a doc type with an alias of "widgetAlias". However if a single doc type is matched, (aka **Single Doc Type Mode**), then doc type selection stage (in the DTGE panel) will be skipped. Note, your document type must be an Element type, in order to be usable in DTGE. |
 | NameTemplate    | String   | Allows using any of the doctype's property values in the name/label: {{propertyAlias}} |
 | EnablePreview   | Boolean  | Enables rendering a preview of the grid cell in the grid editor. |
 | overlaySize     | String   | Define the size of the grid editor dialog. You can write `large`, `medium` or `small`. If no size is set, the grid editor dialog will be small. Note, the medium size requires a minimum Umbraco version of 8.3 |