feat(formatter_htmlish): format end tags of omitted html, head and body (#28388)

Some HTML tags can be written with ommiting it's opening tag.

crates/oxc_formatter_htmlish/src/tree/build/mod.rs

@@ -252,8 +252,10 @@ impl Builder<'_> {
         }
         // CDATA reads as text, merged with the texts around it,
         // and prints as written (DIVERGENCES.md#cdata-as-written).
-        let text_like =
-            matches!(node.kind, NodeKind::Text(_) | NodeKind::Comment(_) | NodeKind::Cdata);
+        let text_like = matches!(
+            node.kind,
+            NodeKind::Text(_) | NodeKind::Comment(_) | NodeKind::Cdata | NodeKind::EndTag(_)
+        );
         let display = self.display(id);
         let facts = self.facts(id);
         facts.self_closing = self_closing;

crates/oxc_formatter_htmlish/src/tree/build/sensitivity.rs

@@ -1,7 +1,7 @@
 //! Whitespace sensitivity: which gaps between nodes render, from CSS display and the options,
 //! past hidden elements and Angular blocks.
 
-use oxc_htmlish_parser::ast::{Element, Namespace, NodeId};
+use oxc_htmlish_parser::ast::{Element, Namespace, NodeId, NodeKind};
 
 use super::{Builder, is_pre_like, is_whitespace_text};
 use crate::{
@@ -14,6 +14,10 @@ impl Builder<'_> {
     /// a `<!-- display: -->` comment overrides it in `children`.
     pub(super) fn display(&self, id: NodeId) -> Display {
         let Some(el) = self.tree.element(id) else {
+            // An omitted element's end tag (`</body>`): no whitespace around it renders
+            if matches!(self.tree.kind(id), NodeKind::EndTag(_)) {
+                return Display::Block;
+            }
             // Text, comments and the document: only the option applies
             return match self.sensitivity {
                 WhitespaceSensitivity::Ignore => Display::Block,

crates/oxc_formatter_htmlish/src/tree/mod.rs

@@ -33,7 +33,7 @@ pub struct Facts {
     pub first_child: Option<NodeId>,
     pub last_child: Option<NodeId>,
     pub display: Display,
-    /// Text and comments: printed without tags whose markers could be borrowed.
+    /// Text, comments and an omitted element's end tag: printed without tags whose markers could be borrowed.
     pub text_like: bool,
     /// No children and no end tag: the start tag closes the node.
     /// Text-like nodes count too.

crates/oxc_formatter_htmlish/tests/fixtures/html/omitted-element-end-tags.html

@@ -0,0 +1 @@
+<!doctype html><title>t</title></head><p>x</p>y<!-- display: inline --></body></html>

crates/oxc_formatter_htmlish/tests/fixtures/html/omitted-element-end-tags.html.snap

@@ -0,0 +1,26 @@
+---
+source: crates/oxc_formatter_htmlish/tests/fixtures/mod.rs
+---
+==================== Input ====================
+<!doctype html><title>t</title></head><p>x</p>y<!-- display: inline --></body></html>
+
+==================== Output ====================
+------------------
+{ printWidth: 80 }
+------------------
+<!doctype html><title>t</title>
+</head>
+<p>x</p>
+y<!-- display: inline --></body>
+</html>
+
+-------------------
+{ printWidth: 100 }
+-------------------
+<!doctype html><title>t</title>
+</head>
+<p>x</p>
+y<!-- display: inline --></body>
+</html>
+
+===================== End =====================