CLI: Update docs for 'aspire resources' renamed to 'aspire describe'

[maddymontaquila]

Context

In dotnet/aspire#14599 (targeting 13.2), the aspire resources command was renamed to aspire describe (with resources kept as a backward-compatible alias).

The --watch flag was also renamed to --follow/-f for consistency with aspire logs --follow.

What needs updating

Any aspire.dev documentation that references:

• aspire resources → should use aspire describe as the primary command name
• aspire resources --watch → should use aspire describe --follow

The old names still work as aliases, but docs should show the new primary names.