Doc updateQueryString: / cleans URL with no query

[Mkranj]

I wanted my app to set the URL to the starting value, with no "?query=value" at the end. I've found out that using updateQueryString("/") does the trick, while using "", NA or NULL as the argument didn't do anything. I'm sure this could be useful to someone else, so I wrote about it in the function documentation.

[CLAassistant]

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