Document breaking changes to index_management, license_management, ro…

…llup, and upgrade_assistant settings in kibana.yml. (elastic#30569)

docs/migration/migrate_7_0.asciidoc

@@ -204,11 +204,27 @@ dependent on an unspecified port set to 9200, `:9200` will have to be appended t
 *Impact:* Users with `elasticsearch.ssl.verify` set should use `elasticsearch.ssl.verificationMode` instead.
 Previously set `elasticsearch.ssl.verify` is equal to `elasticsearch.ssl.verificationMode: full`.
 
+[float]
+=== kibana.yml setting `index_management.<any setting>` is no longer valid
+*Impact:* Users with `index_management.<any setting>` set should use `xpack.index_management.<any setting>` instead.
+
+[float]
+=== kibana.yml setting `license_management.<any setting>` is no longer valid
+*Impact:* Users with `license_management.<any setting>` set should use `xpack.license_management.<any setting>` instead.
+
+[float]
+=== kibana.yml setting `rollup.<any setting>` is no longer valid
+*Impact:* Users with `rollup.<any setting>` set should use `xpack.rollup.<any setting>` instead.
+
+[float]
+=== kibana.yml setting `upgrade_assistant.<any setting>` is no longer valid
+*Impact:* Users with `upgrade_assistant.<any setting>` set should use `xpack.upgrade_assistant.<any setting>` instead.
+
 [float]
 === Legacy browsers (namely IE11) will see a security warning message whenever they load Kibana
 *Details:* Kibana now has a Content Security Policy, but it's only effective if browsers enforce it, and since older
 browsers like Internet Explorer 11 do not support CSP, we show them a warning message whenever they load Kibana.
 
 *Impact:* Nothing needs to be done necessarily, but if you don't need to support legacy browsers like IE11, we recommend
 that you set `csp.strict: true` in your kibana.yml to block access to those browsers entirely. If your organization requires
-users to use IE11, you might like to disable the warning entirely with `csp.warnLegacyBrowsers: false` in your kibana.yml.
+users to use IE11, you might like to disable the warning entirely with `csp.warnLegacyBrowsers: false` in your kibana.yml.