Prettify capacity contant definition a little.

Author: ImmemorConsultrixContrarie

src/inline_string.rs

@@ -39,6 +39,7 @@ use std::convert::{Infallible, TryFrom};
 use std::fmt::{self, Display};
 use std::hash;
 use std::io::Write;
+use std::mem;
 use std::ops::{self, RangeBounds};
 use std::ptr;
 use std::str;
@@ -49,14 +50,8 @@ use std::str;
 /// Sometime in the future, when Rust's generics support specializing with
 /// compile-time static integers, this number should become configurable.
 pub const INLINE_STRING_CAPACITY: usize = {
-    #[cfg(target_pointer_width = "64")]
-    {
-        30
-    }
-    #[cfg(target_pointer_width = "32")]
-    {
-        14
-    }
+    use mem::size_of;
+    size_of::<String>() + size_of::<usize>() - 2
 };
 
 /// A short UTF-8 string that uses inline storage and does no heap allocation.