Implement a more robust way of locating rust-analyzer

When bundled, we will retrieve it out of the `Resources` folder.
Locally, we're expected to run `script/download-rust-analyzer` and
put `vendor/bin` in our $PATH.

.github/workflows/ci.yml

@@ -32,6 +32,11 @@ jobs:
         with:
           clean: false
 
+      - name: Download rust-analyzer
+        run: |
+          script/download-rust-analyzer
+          echo "$PWD/vendor/bin" >> $GITHUB_PATH
+
       - name: Run tests
         run: cargo test --workspace --no-fail-fast
 
@@ -63,6 +68,9 @@ jobs:
         with:
           clean: false
 
+      - name: Download rust-analyzer
+        run: script/download-rust-analyzer
+
       - name: Create app bundle
         run: script/bundle