Rollup merge of #125158 - Nilstrieb:block-indent, r=compiler-errors

hir pretty: fix block indent

before:
```rust
fn main() {
        {
                {
                        ::std::io::_print(format_arguments::new_const(&["Hello, world!\n"]));
                    };
            }
    }
```
after:
```rust
fn main() {
    {
        {
            ::std::io::_print(format_arguments::new_const(&["Hello, world!\n"]));
        };
    }
}
```

AST pretty does the same.

compiler/rustc_hir_pretty/src/lib.rs

@@ -1454,7 +1454,7 @@ impl<'a> State<'a> {
                     self.word_space(":");
                 }
                 // containing cbox, will be closed by print-block at `}`
-                self.cbox(INDENT_UNIT);
+                self.cbox(0);
                 // head-box, will be closed by print-block after `{`
                 self.ibox(0);
                 self.print_block(blk);

tests/pretty/issue-4264.pp

@@ -17,9 +17,9 @@ fn bar() ({
     let _: [(); (1 as usize)] = ([(() as ())] as [(); 1]);
 
     let _ =
-            (((&([(1 as i32), (2 as i32), (3 as i32)] as [i32; 3]) as
+        (((&([(1 as i32), (2 as i32), (3 as i32)] as [i32; 3]) as &[i32; 3])
-                        &[i32; 3]) as *const _ as *const [i32; 3]) as
+                as *const _ as *const [i32; 3]) as *const [i32; (3 as usize)]
-                *const [i32; (3 as usize)] as *const [i32; 3]);
+            as *const [i32; 3]);
 
 
 

tests/ui/unpretty/flattened-format-args.stdout

@@ -9,7 +9,7 @@ fn main() {
     let x = 1;
     // Should flatten to println!("a 123 b {x} xyz\n"):
     {
-                ::std::io::_print(format_arguments::new_v1(&["a 123 b ",
+        ::std::io::_print(format_arguments::new_v1(&["a 123 b ", " xyz\n"],
-                                    " xyz\n"], &[format_argument::new_display(&x)]));
+                &[format_argument::new_display(&x)]));
     };
 }