[Doc] Correct jdbc url example
Adds a missing `?` to separate the url parameters.
@@ -129,7 +129,7 @@ To put all of it together, the following URL:
["source","text"]
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-jdbc:es://http://server:3456/timezone=UTC&page.size=250
+jdbc:es://http://server:3456/?timezone=UTC&page.size=250
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Opens up a {es-sql} connection to `server` on port `3456`, setting the JDBC connection timezone to `UTC` and its pagesize to `250` entries.
