It was defined once, but it was passed into various functions. This
added unnecessary complexity.
It is now defined in a constants file, which is imported where
necessary.
TypeScript is better at inferring types when using simple functions and
objects instead of classes. As a result many type annotations have now
been removed without impacting type safety.
Some other benefits are this can be minified better and private fields
are now truly private variables.
This removes the need to explain certain statements and imports need to
happen in a specific order. Users can now just use:
```ts
import { setDiagnosticsOptions } from 'monaco-yaml';
setDiagnosticsOptions({});
```
This is a preparation for `monaco-editor@^0.22.0`. In this version the global
`monaco` object was removed for ESM users.
A choice was made to use `monaco-editor` imports, because this probably has
best compatibility for most users. If users want to use `monaco-editor-core`,
they will have to create an alias in their own build process.
