Makes some suggested documentation improvements

Signed-off-by: Brian Fletcher <brian@roadie.io>

docs/plugins/github-apps.md

@@ -96,7 +96,7 @@ optionally include the `allowedInstallationOwners` option.
 
 ```yaml
 appId: 1
-allowedInstallationOwners: [1234]
+allowedInstallationOwners: ['GlobexCorp']
 clientId: client id
 clientSecret: client secret
 webhookSecret: webhook secret

packages/integration/src/github/config.ts

@@ -94,7 +94,11 @@ export type GithubAppConfig = {
    */
   clientSecret: string;
   /**
-   * List of installation owners allowed to be used by this backstage https://github.com/app/installations/$InstallationId
+   * List of installation owners allowed to be used by this GitHub app. The GitHub UI does not provide a way to list the installations.
+   * However you can list the installations with the GitHub API. You can find the list of installations here:
+   * https://api.github.com/app/installations
+   * The relevant documentation for this is here.
+   * https://docs.github.com/en/rest/reference/apps#list-installations-for-the-authenticated-app--code-samples
    */
   allowedInstallationOwners?: string[];
 };