The "manipulating property sources" example in the Javadoc for `ConfigurableEnvironment` states that `MutablePropertySources` expect a `Map<String,String>`; whereas it expects a `Map<String,Object>`. Closes gh-29693
The "manipulating property sources" example in the Javadoc for `ConfigurableEnvironment` states that `MutablePropertySources` expect a `Map<String,String>`; whereas it expects a `Map<String,Object>`. Closes gh-29693