rustdoc: add method spacing to trait methods

More cleanup for 8846c08, this time in trait
layouts when things are collapsed.

Author: notriddle

src/librustdoc/html/render/print_item.rs

@@ -716,7 +716,7 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
         document(&mut content, cx, m, Some(t), HeadingOffset::H5);
         let toggled = !content.is_empty();
         if toggled {
-            write!(w, "<details class=\"rustdoc-toggle\" open><summary>");
+            write!(w, "<details class=\"rustdoc-toggle method-toggle\" open><summary>");
         }
         write!(w, "<div id=\"{}\" class=\"method has-srclink\">", id);
         render_rightside(w, cx, m, t, RenderMode::Normal);

src/librustdoc/html/static/css/rustdoc.css

@@ -2011,7 +2011,8 @@ in storage.js plus the media query with (min-width: 701px)
 
 .method-toggle summary,
 .implementors-toggle summary,
-.impl {
+.impl,
+#implementors-list > .docblock {
 	margin-bottom: 0.75em;
 }