Revert "feat: Documentation.toJson() can handle nested submodules (#1190

)"

This reverts commit 9036833.

src/docgen/view/documentation.ts

@@ -312,29 +312,22 @@ export class Documentation {
   }
 
   /**
-   * Lookup a submodule by a submodule name. To look up a nested submodule, encode it as a
-   * dot-separated path, e.g., 'top-level-module.nested-module.another-nested-one'.
+   * Lookup a submodule by a submodule name.
    */
   private findSubmodule(assembly: reflect.Assembly, submodule: string): reflect.Submodule {
-    type ReflectSubmodules = typeof assembly.submodules;
-    return recurse(submodule.split('.'), assembly.submodules);
+    const submodules = assembly.submodules.filter(
+      (s) => s.name === submodule,
+    );
 
-    function recurse(names: string[], submodules: ReflectSubmodules): reflect.Submodule {
-      const [head, ...tail] = names;
-      const found = submodules.filter(
-        (s) => s.name === head,
-      );
-
-      if (found.length === 0) {
-        throw new Error(`Submodule ${submodule} not found in assembly ${assembly.name}@${assembly.version}`);
-      }
-
-      if (found.length > 1) {
-        throw new Error(`Found multiple submodules with name: ${submodule} in assembly ${assembly.name}@${assembly.version}`);
-      }
+    if (submodules.length === 0) {
+      throw new Error(`Submodule ${submodule} not found in assembly ${assembly.name}@${assembly.version}`);
+    }
 
-      return tail.length === 0 ? found[0] : recurse(tail, found[0].submodules);
+    if (submodules.length > 1) {
+      throw new Error(`Found multiple submodules with name: ${submodule} in assembly ${assembly.name}@${assembly.version}`);
     }
+
+    return submodules[0];
   }
 
   private async createAssembly(