[DOC release] Cleanup application API code examples

Quotes, vars, spaces
[BUGFIX beta] Assert existence of `name` property for registered initializers
Merge pull request #9513 from knownasilya/patch-2

[DOC release] Cleanup application api code examples
Merge pull request #9514 from vinilios/initializer-assertion

[BUGFIX beta] Assert name property exists when registering an application initializer