remove cfg bootstrap from library tree

Signed-off-by: onur-ozkan <work@onurozkan.dev>

Author: onur-ozkan

library/core/src/fmt/rt.rs

@@ -16,14 +16,6 @@ pub struct Placeholder {
     pub width: Count,
 }
 
-#[cfg(bootstrap)]
-impl Placeholder {
-    #[inline]
-    pub const fn new(position: usize, flags: u32, precision: Count, width: Count) -> Self {
-        Self { position, flags, precision, width }
-    }
-}
-
 /// Used by [width](https://doc.rust-lang.org/std/fmt/#width)
 /// and [precision](https://doc.rust-lang.org/std/fmt/#precision) specifiers.
 #[lang = "format_count"]