Move equal sign back into head ibox

Author: dtolnay

Diff for: compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -1116,9 +1116,11 @@ impl<'a> State<'a> {
         self.print_ident(ident);
         self.word_space(":");
         self.print_type(ty);
+        if body.is_some() {
+            self.space();
+        }
         self.end(); // end the head-ibox
         if let Some(body) = body {
-            self.space();
             self.word_space("=");
             self.print_expr(body);
         }

Diff for: src/test/pretty/issue-68710-field-attr-proc-mac-lost.rs

@@ -7,8 +7,7 @@ struct C {
 }
 
 #[allow()]
-const C: C
-    =
+const C: C =
     C{
       #[cfg(debug_assertions)]
       field: 0,

Diff for: src/test/ui/proc-macro/quote-debug.stdout

@@ -43,8 +43,7 @@ fn main() {
      crate::TokenStream::from(crate::TokenTree::Punct(crate::Punct::new('\u{3b}',
                                                                         crate::Spacing::Alone)))].iter().cloned().collect::<crate::TokenStream>()
 }
-const _: ()
-    =
+const _: () =
     {
         extern crate proc_macro;
         #[rustc_proc_macro_decls]