fix(config): improve config:best-practices description (#31517)

lib/config/presets/internal/config.ts

@@ -4,13 +4,13 @@ import type { Preset } from '../types';
 
 export const presets: Record<string, Preset> = {
   'best-practices': {
-    configMigration: true,
     description:
       'Preset with best practices from the Renovate maintainers. Recommended for advanced users, who want to follow our best practices.',
     extends: [
       'config:recommended',
       'docker:pinDigests',
       'helpers:pinGitHubActionDigests',
+      ':configMigration',
       ':pinDevDependencies',
     ],
   },

lib/config/presets/internal/default.ts

@@ -124,6 +124,10 @@ export const presets: Record<string, Preset> = {
       'Do not separate `patch` and `minor` upgrades into separate PRs for the same dependency.',
     separateMinorPatch: false,
   },
+  configMigration: {
+    configMigration: true,
+    description: 'Enable Renovate configuration migration PRs when needed.',
+  },
   dependencyDashboard: {
     dependencyDashboard: true,
     description: 'Enable Renovate Dependency Dashboard creation.',