feat(config): mergeable repositoryAliases global option (#26848)

Author: eschleining

lib/config/options/index.ts

@@ -979,6 +979,7 @@ const options: RenovateOptions[] = [
   {
     name: 'registryAliases',
     description: 'Aliases for registries.',
+    mergeable: true,
     type: 'object',
     default: {},
     additionalProperties: {

lib/workers/repository/extract/extract-fingerprint-config.spec.ts

@@ -7,7 +7,7 @@ describe('workers/repository/extract/extract-fingerprint-config', () => {
   it('filter with enabledManagers', () => {
     const config = mergeChildConfig(getConfig(), {
       registryAliases: {
-        stable: 'http://some.link', // intentionally placing the field incorrectly
+        stable: 'http://some.link',
       },
       ignorePaths: ['ignore-path-1'],
       includePaths: ['include-path-1'],
@@ -47,6 +47,7 @@ describe('workers/repository/extract/extract-fingerprint-config', () => {
       npmrcMerge: false,
       registryAliases: {
         notStable: 'http://some.link.2',
+        stable: 'http://some.link',
       },
       skipInstalls: null,
     });