Style cm-scroller with overflow-anchor: none to prevent some buggy Ch…

…rome scrolling

FIX: Avoid an issue where Chrome would incorrectly scroll the window when deleting lines
in the editor.

See https://discuss.codemirror.net/t/why-delete-line-makes-parent-element-scroll/8524

src/theme.ts

@@ -48,7 +48,8 @@ export const baseTheme = buildTheme("." + baseThemeID, {
     height: "100%",
     overflowX: "auto",
     position: "relative",
-    zIndex: 0
+    zIndex: 0,
+    overflowAnchor: "none",
   },
 
   ".cm-content": {