fix: kibana dev server not restarting for external plugin elastic#171260

 (elastic#198246)

## Summary

Fixes elastic#171260 the Kibana dev server not restarting during external
plugin development for server side code.

### Checklist


### For maintainers

- [ ] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#_add_your_labels)
- [ ] This will appear in the **Release Notes** and follow the
[guidelines](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

## Release note
Fixes elastic#171260 the Kibana dev server not restarting during external
plugin development for server side code.

---------

Co-authored-by: Brad White <[email protected]>

packages/kbn-cli-dev-mode/src/watcher.ts

@@ -26,7 +26,8 @@ const packageMatcher = makeMatcher([
 /**
  * Any code that is outside of a package must match this in order to trigger a restart
  */
-const nonPackageMatcher = makeMatcher(['config/**/*.yml']);
+const nonPackageMatcher = makeMatcher(['config/**/*.yml', 'plugins/**/server/**/*']);
+const staticFileMatcher = makeMatcher(['plugins/**/kibana.json']);
 
 export interface Options {
   enabled: boolean;
@@ -87,6 +88,10 @@ export class Watcher {
           if (result.type === 'non-package') {
             return nonPackageMatcher(result.repoRel) && fire(result.repoRel);
           }
+
+          if (result.type === 'static') {
+            return staticFileMatcher(result.repoRel) && fire(result.repoRel);
+          }
         }
       },
       {