Put leading | in patterns under OrPat

Previously it was one level above, and that caused problems with macros that expand to it, because macros expect to get only one top-level node.

crates/syntax/src/ast/generated/nodes.rs

@@ -1283,6 +1283,8 @@ pub struct OrPat {
 impl OrPat {
     #[inline]
     pub fn pats(&self) -> AstChildren<Pat> { support::children(&self.syntax) }
+    #[inline]
+    pub fn pipe_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![|]) }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]

crates/syntax/src/ast/node_ext.rs

@@ -1140,3 +1140,13 @@ impl From<ast::AssocItem> for ast::AnyHasAttrs {
         Self::new(node)
     }
 }
+
+impl ast::OrPat {
+    pub fn leading_pipe(&self) -> Option<SyntaxToken> {
+        self.syntax
+            .children_with_tokens()
+            .find(|it| !it.kind().is_trivia())
+            .and_then(NodeOrToken::into_token)
+            .filter(|it| it.kind() == T![|])
+    }
+}