docs: Don't cache example files

[aleksanderkatan]

Currently, all example files except for index.ts are cached. This makes it impossible to create a root in a file other than index.ts, because it will be cleaned up on example change, and on another example load it will attempt to create resources from a destroyed root.

Investigate whether this is necessary.

Potential benefits of this change:

• cleaner example code with less slots/wrappers for resource creation,
• easier point of entry for potential external example creators (it has already happened twice that somebody attempted delegating root to another file, and needed to refactor),
• less memory usage when opening multiple examples in a single session.