Move flexbox handling up to the explorer component.

src/Editor.module.css

@@ -1,7 +1,4 @@
 .EditorTextWrapper {
-  /* TODO: This flex should be in the parent */
-  flex: 1;
-  flex-basis: 0;
   position: relative;
   background: white;
   font-family: ui-monospace, "Cascadia Code", "Source Code Pro", Menlo, Consolas,

src/Explorer.module.css

@@ -3,4 +3,9 @@
   flex-direction: row;
   height: 100%;
   width: 100%;
+
+  > * {
+    flex: 1;
+    flex-basis: 0;
+  }
 }

src/OrgAst.module.css

@@ -1,5 +1,4 @@
 .OrgAst {
-  flex: 1;
   background: #eeeeee;
   padding: 5px;
   overflow: auto;