docs: note that autoreload requires shiny::runApp()

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 34.11%. Comparing base (11b969a) to head (fadd049).

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #567 +/- ## ======================================= Coverage 34.11% 34.11% ======================================= Files 10 10 Lines 554 554 ======================================= Hits 189 189 Misses 365 365 ```

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