Update Categories Document (SharePoint#842)

* Fix "Discovery".

* Update the description for the group and groupId property.

* Fix the column name for corresponding classic page category name.

Author: lijunle

docs/spfx/web-parts/guidance/simplify-adding-web-parts-with-preconfigured-entries.md

@@ -47,17 +47,17 @@ title                   |ILocalizedString|yes     |The web part title that is di
 description             |ILocalizedString|yes     |The web part description that is displayed in the toolbox tooltips.|`"description": { "default": "Shows weather in the given ___location", "nl-nl": "Toont weerbericht voor de opgegeven locatie" } `
 officeFabricIconFontName|string          |no      |The icon for the web part that is displayed in the toolbox. Its value must be one of the [Office UI Fabric icon names](https://dev.office.com/fabric#/styles/icons). If this property has a value, the **iconImageUrl** property will be ignored.|`"officeFabricIconFontName": "Sunny"`
 iconImageUrl            |string          |no      |The icon for the web part that is displayed in the toolbox and is represented by an image URL. The image at the URL must be exactly 40 x 28 px. If the **officeFabricIconName** property does not have a value, this property must have a value.|`"iconImageUrl": "https://cdn.contoso.com/weather.png"`
-groupId                 |string          |yes     |The group id determines which toolbox group will contain the web part. The SharePoint Framework reserves group ids for default groups. The developer can pick one of those groups. If a group id is specified, then the **group** property will be ignored. Alternatively, the developer can pick a completely unique id and a group name. The toolbox will then show the web part in its own group.|`"groupId": "6737645a-4443-4210-a70e-e5e2a219133a"`
-group                   |ILocalizedString|no      |The name of the group in the toolbox in which the web part will be displayed. If no value is provided, then the web part will be displayed in the **Custom** group.|`"group": { "default": "Content", "nl-nl": "Inhoud" }`
+groupId                 |string          |yes     |The group ID determines which toolbox group will contain the web part. The client-side framework has reserved group IDs for predefined groups. The developer can pick one of those groups.|`"groupId": "cf066440-0614-43d6-98ae-0b31cf14c7c3"`
+group                   |ILocalizedString|no      |This field is used to determine which toolbox group will contain the web part in the authoring experience. On classic pages, the web part gallery is equivalent to the toolbox. When you choose a GUID as a group ID (as in the table below), use the corresponding classic page category name from the predefined group.|`"group": { "default": "Media and Content" }`
 dataVersion             |string          |no      |Use this field to specify the data version of the pre-configured data provided to the web part. Note that data version is different from the version field in the manifest. The manifest version is used to control the versioning of the web part code, while data version is used to control the versioning of the serialized data of the web part. Refer to dataVersion field of your web part for more information. Supported values format: MAJOR.MINOR version|`"dataVersion": "1.0"`
 properties              |TProperties     |yes     |A Key-value pair object with default values for web part properties.|`"properties": { "___location": "Redmond", "numberOfDays": 3, "showIcon": true }`
 
 Out of the box Categories are following, which can be used for the `groupId` property.
 
-Category Name |Guid |Map to web part picker |Description        
+Category Name |Guid |Corresponding classic page category name |Description        
 --- |--- |--- |---
 Text, media, and content | `cf066440-0614-43d6-98ae-0b31cf14c7c3`| Media and Content  |This category includes web parts that display text, multi-media, documents, information from the web, and other rich content.   
-Discover | `1edbd9a8-0bfb-4aa2-9afd-14b8c45dd489`| Discovery  |This category includes web parts that organize, group, and filter content to help users discover information. 
+Discovery | `1edbd9a8-0bfb-4aa2-9afd-14b8c45dd489`| Discovery  |This category includes web parts that organize, group, and filter content to help users discover information. 
 Communication and collaboration | `75e22ed5-fa14-4829-850a-c890608aca2d`| Social Collaboration |This category includes web parts that facilitate information sharing, team work, and social interactions.
 Planning and process | `1bc7927e-4a5e-4520-b540-71305c79c20a`| Business Data | This category includes web parts that empower team productivity with the use of planning and process tools. 
 Business and intelligence | `4aca9e90-eff5-4fa1-bac7-728f5f157b66`| Business Data | This category includes web parts for tracking and analyzing data, and for integrating business flow with pages.