Improve Codespaces + C# extension interaction (#33614)

Author: captainsafia

.devcontainer/devcontainer.json

@@ -18,6 +18,11 @@
 		"ms-dotnettools.csharp"
 	],
 
+	"settings": {
+		// Loading projects on demand is better for larger codebases
+		"omnisharp.enableMsBuildLoadProjectsOnDemand": true
+	},
+
 	// Use 'postCreateCommand' to run commands after the container is created.
 	"onCreateCommand": "bash -i ${containerWorkspaceFolder}/.devcontainer/scripts/container-creation.sh",
 

.devcontainer/scripts/container-creation.sh

@@ -6,4 +6,6 @@ set -e
 # the repo directory on the container so we do this post-create
 git submodule update --init --recursive
 # Install SDK and tool dependencies before container starts
-./eng/build.sh --only-build-repo-tasks
+# Also run the full restore on the repo so that go-to definition
+# and other language features will be available in C# files
+./restore.sh