Update VSCode settings to resolve files named `script` as shell scripts (#2419)

## Why
VSCode for me resolves `script` as YAML files showing incorrect syntax
coloring. This setting forces VSCode to treat all files named `script`
as shell scripts leading to better syntax highlighting.

These files are common place in our acceptance tests.

## Tests
Manually.

.vscode/settings.json

@@ -17,5 +17,8 @@
     "python.envFile": "${workspaceRoot}/.env",
     "python.analysis.stubPath": ".vscode",
     "jupyter.interactiveWindow.cellMarker.codeRegex": "^# COMMAND ----------|^# Databricks notebook source|^(#\\s*%%|#\\s*\\<codecell\\>|#\\s*In\\[\\d*?\\]|#\\s*In\\[ \\])",
-    "jupyter.interactiveWindow.cellMarker.default": "# COMMAND ----------"
+    "jupyter.interactiveWindow.cellMarker.default": "# COMMAND ----------",
+    "files.associations": {
+        "script": "shellscript"
+    }
 }