feat(slhx): prefer render methods for views

Move view rendering onto Slot::render and KeyedSlot append/prepend/replace extension methods, leaving explicit text/html methods for non-view escape hatches.

req: codegen/002

req: view/001

examples/v0/src/lib.rs

@@ -77,7 +77,7 @@ mod tests {
     fn todos_append_keyed_rows_from_form_input() {
         fn add_todo(input: TodoInput) -> impl IntoEffect {
             let todo = Todo { id: 7, title: input.title };
-            ui::slots::todo_row.append_view(
+            ui::slots::todo_row.append(
                 todo.id.to_string(),
                 &TodoRow { title: todo.title },
             )
@@ -121,7 +121,7 @@ mod tests {
     fn page_swap_updates_content_and_history() {
         fn load_docs() -> impl IntoEffect {
             (
-                ui::slots::content.render_view(&DocsContent {
+                ui::slots::content.render(&DocsContent {
                     message: "This page was swapped.",
                 }),
                 ui::slots::title.text("Docs"),