scroll to top when clicking fresh link

but don't disrupt the already working scroll history

We can detect if a hash change occurs due to history navigation
(forward/back) or a direct link click by putting an empty object in
History.state, and checking if it is null or not upon hash change.

README.md

@@ -58,11 +58,11 @@ what you want.
 * add source view links, currently you have to use the keyboard shortcut
 * make the search box and nav bar stretch to fit the window
 * redundant search results (search "format")
-* scroll to top when clicking fresh link. but don't disrupt the already working scroll history
 * convert TODO comments into roadmap
 
 ## Post-Merge Roadmap
 
+* infer comptime_int constants (example: members of `#std.time`)
 * when global const has a type of `type`, categorize it as a type despite its value
   - example: `std.DynLib` (requires patching to add type annotation)
 * show abbreviated doc comments in types and namespaces listings

lib/main.js

@@ -102,11 +102,11 @@
 
         updateModuleList();
 
-        window.addEventListener('hashchange', onHashChange, false);
+        window.addEventListener('popstate', onPopState, false);
         domSearch.addEventListener('keydown', onSearchKeyDown, false);
         domSearch.addEventListener('input', onSearchChange, false);
         window.addEventListener('keydown', onWindowKeyDown, false);
-        onHashChange();
+        onHashChange(null);
       });
     });
 
@@ -579,8 +579,14 @@
         }
     }
 
-    function onHashChange() {
+    function onHashChange(state) {
+      history.replaceState({}, "");
       navigate(location.hash);
+      if (state == null) window.scrollTo({top: 0});
+    }
+
+    function onPopState(ev) {
+      onHashChange(ev.state);
     }
 
     function navigate(location_hash) {

src/Walk.zig

@@ -130,7 +130,7 @@ pub const File = struct {
             const node_tags = ast.nodes.items(.tag);
             const node_datas = ast.nodes.items(.data);
             const main_tokens = ast.nodes.items(.main_token);
-            log.debug("categorize_expr tag {s}", .{@tagName(node_tags[node])});
+            //log.debug("categorize_expr tag {s}", .{@tagName(node_tags[node])});
             return switch (node_tags[node]) {
                 .container_decl,
                 .container_decl_trailing,