Fix some styling issues

plugs/markdown/assets/preview.css

@@ -1,3 +1,9 @@
+html,
+html {
+  overflow-y: scroll !important;
+  width: 90% !important
+}
+
 body {
   font-family: georgia, times, serif;
   font-size: 14pt;

web/editor_ui.tsx

@@ -240,7 +240,7 @@ export class MainUI {
               : [],
             {
               icon: HomeIcon,
-              description: `Go home (Alt-h)`,
+              description: `Go to the index page (Alt-h)`,
               callback: () => {
                 editor.navigate("");
               },

web/styles/editor.scss

@@ -451,7 +451,7 @@
       width: 100%;
       max-width: 100%;
       padding: 0;
-      margin: 0;
+      margin: 0 0 -2ch 0;
       border: 1px solid var(--editor-directive-background-color);
       border-radius: 5px;
     }