Mention default set of fileNesting patterns in setting description

[weinand]

While verifying #142341 I was not aware of the fact that the setting "explorer.experimental.fileNesting.enabled": true comes with a full set of implicit default patterns even if no "explorer.experimental.fileNesting.patterns" exists in the settings.json. Only when modifying the default set, will the "explorer.experimental.fileNesting.patterns" setting show up.

The setting description need to make this clearer!

[JacksonKearl]

This is roughly equivalent to what the file/search exclude already does today:

[lramos15]

Closing due to following other patterns. What specifically drove you to thinking they're examples maybe we could work on polishing the settings UI.