Syntax fixes (#5367)

* Declare return types on functions

And a very few other type related minor fixes

* Minor syntax fixes

* Remove unnecessary escape chars in regexes
* Remove unnecessary awaits
* Replace deprecated req.connection with req.socket
* Replace deprecated upload with uploadOne
* Remove unnecessary eslint-disable-next-line comments
* Comment empty functions / catch or finally clauses
* Fix irregular whitespaces
* Add missing returns (null)
* Remove unreachable code
* A few logical fixes
* Remove / Handle non-null assertions which are certainly unnecessary (e.g. in
tests)

api/src/utils/reduce-schema.ts

@@ -11,7 +11,7 @@ import { uniq } from 'lodash';
 export function reduceSchema(
 	schema: SchemaOverview,
 	actions: PermissionsAction[] = ['create', 'read', 'update', 'delete']
-) {
+): SchemaOverview {
 	const reduced: SchemaOverview = {
 		collections: {},
 		relations: [],