meta(vscode): Make rust-analyzer run Clippy (#2665)

Having this setting ensures that any linter warnings (at least, for the
developer's system) are displayed in the IDE. I have had it enabled in
my user settings for awhile, but we should also ensure it is set in the
project settings, so that future Sentry CLI contributors have this
setting enabled out of the box.

Author: szokeasaurusrex

.vscode/settings.json

@@ -1,4 +1,5 @@
 {
     "rust-analyzer.cargo.features": ["unstable-mobile-app"],
-    "rust-analyzer.cargo.noDefaultFeatures": false
+    "rust-analyzer.cargo.noDefaultFeatures": false,
+    "rust-analyzer.check.command": "clippy"
 }