Disable basic PHP completion in Codespace

This competes with the completions provided by
https://github.com/felixfbecker/vscode-php-intellisense.

Thus disabling the completions is recommended.

Signed-off-by: Lukas Reschke <lukas@statuscode.ch>

.devcontainer/devcontainer.json

@@ -16,4 +16,7 @@
 		"felixfbecker.php-intellisense",
 		"ms-azuretools.vscode-docker"
 	],
-}
+	"settings": {
+		"php.suggest.basic": false,
+	}
+}