Force a recompute of the monaco editor height

Monaco allocates height on initialization, and sets this as a fixed
height. By removing the height on a resize of the body, we force monaco
to recompute the value and claim all newly available space of the
flexbox layout.

Note that we use a resize observer instead of a `$(window).resize`, as
this will also trigger for other DOM changes and not just viewport
changes.

Author: Kevinjil

webapp/public/js/domjudge.js

@@ -1561,3 +1561,15 @@ function initDiffEditorTab(editorId, diffId, submissionId, models) {
     }
     diffEditor.onDidUpdateDiff(updateIcon);
 }
+
+// Force a recompute of the monaco editor height when the display size changes.
+if ('ResizeObserver' in window) {
+    $(() => {
+        var monacoObserver = new ResizeObserver(() => {
+            document.querySelectorAll('.monaco-editor').forEach(e => {
+                e.style.height = "0";
+            });
+        });
+        monacoObserver.observe(document.body);
+    });
+}