Convert a README to mdx to get it slurped up by the new docs system (#84834) (#85335)

* Convert readme to mdx so it can get slurped into the new docs system

* Adjust plugin list doc generation so it accounts for mdx readmes

* fix eslint of discover_plugin file

* Fix link to readme in plugin list

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

docs/developer/plugin-list.asciidoc

@@ -45,7 +45,7 @@ NOTE:
 - Adds a dashboard embeddable that can be used in other applications.
 
 
-|{kib-repo}blob/{branch}/src/plugins/data/README.md[data]
+|{kib-repo}blob/{branch}/src/plugins/data/README.mdx[data]
 |The data plugin provides common data access services, such as search and query, for solutions and application developers.
 
 

packages/kbn-dev-utils/src/plugin_list/discover_plugins.ts

@@ -38,7 +38,9 @@ export interface Plugin {
 export type Plugins = Plugin[];
 
 const getReadmeName = (directory: string) =>
-  Fs.readdirSync(directory).find((name) => name.toLowerCase() === 'readme.md');
+  Fs.readdirSync(directory).find(
+    (name) => name.toLowerCase() === 'readme.md' || name.toLowerCase() === 'readme.mdx'
+  );
 
 const getReadmeAsciidocName = (directory: string) =>
   Fs.readdirSync(directory).find((name) => name.toLowerCase() === 'readme.asciidoc');

src/dev/precommit_hook/casing_check_config.js

@@ -30,6 +30,7 @@ export const IGNORE_FILE_GLOBS = [
   'docs/**/*',
   '**/bin/**/*',
   '**/+([A-Z_]).md',
+  '**/+([A-Z_]).mdx',
   '**/+([A-Z_]).asciidoc',
   '**/LICENSE',
   '**/*.txt',

src/plugins/data/README.mdx

@@ -1,3 +1,13 @@
+---
+id: kibDataPlugin
+slug: /kibana-dev-guide/services/data-plugin
+title: Data services
+image: https://source.unsplash.com/400x175/?Search
+summary: The data plugin contains services for searching, querying and filtering.
+date: 2020-12-02
+tags: ['kibana','dev', 'contributor', 'api docs']
+---
+
 # data
 
 The data plugin provides common data access services, such as `search` and `query`, for solutions and application developers.