docs(js): Add sourcemaps explain to source maps troubleshooting guide (#5076)

Author: kamilogorek

src/platforms/javascript/common/sourcemaps/troubleshooting_js.mdx

@@ -6,7 +6,16 @@ description: "Troubleshooting for source maps."
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-Source maps can sometimes be tricky to get going. If you’re having trouble:
+Source maps can sometimes be tricky to get going. If you’re having trouble, you can try using our verification tool inside `sentry-cli`, or go through the steps listed below yourself. Please keep in mind, that the `sentry-cli` is a work-in-progress, and we’re actively working to improve it.
+
+To use the automated verification process, [install and configure](/product/cli/) `sentry-cli`. Once completed, use the `sourcemaps explain` command, by calling it with the event ID that can be found at the top of the **Issue Details** page in [sentry.io](https://sentry.io). For example, "Event fdfd1337e3964cd6a4d11f35357a4c43 | JSON (42.0 KiB)".
+
+```shell
+sentry-cli sourcemaps explain fdfd1337e3964cd6a4d11f35357a4c43
+```
+
+This should provide you with some useful hints about what exactly went wrong with the source maps setup process.
+If it doesn’t, let us know so we can make it better.
 
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