test(examples): render hemplate views into buffers

Use hemplate render_into in public examples and example tests instead of the string-returning render helper, preserving SafeHtml wrapping only at the explicit effect boundary.

req: view/001

req: html_safety/002

examples/v0/src/main.rs

@@ -222,7 +222,11 @@ fn render_html(template: &impl Hemplate) -> SafeHtml {
 }
 
 fn render_template(template: &impl Hemplate) -> String {
-    template.render().expect("v0 hemplate view renders")
+    let mut html = String::new();
+    template
+        .render_into(&mut html)
+        .expect("v0 hemplate view renders");
+    html
 }
 
 #[cfg(test)]