make with_hasher_in const (consistent with with_hasher)

Signed-off-by: TennyZhuang <zty0826@gmail.com>

Author: TennyZhuang

src/map.rs

@@ -429,7 +429,8 @@ impl<K, V, S, A: Allocator + Clone> HashMap<K, V, S, A> {
     /// Creates an empty `HashMap` which will use the given hash builder to hash
     /// keys. It will be allocated with the given allocator.
     ///
-    /// The created map has the default initial capacity.
+    /// The hash map is initially created with a capacity of 0, so it will not
+    /// allocate until it is first inserted into.
     ///
     /// Warning: `hash_builder` is normally randomly generated, and
     /// is designed to allow HashMaps to be resistant to attacks that
@@ -447,7 +448,7 @@ impl<K, V, S, A: Allocator + Clone> HashMap<K, V, S, A> {
     /// map.insert(1, 2);
     /// ```
     #[cfg_attr(feature = "inline-more", inline)]
-    pub fn with_hasher_in(hash_builder: S, alloc: A) -> Self {
+    pub const fn with_hasher_in(hash_builder: S, alloc: A) -> Self {
         Self {
             hash_builder,
             table: RawTable::new_in(alloc),

src/raw/mod.rs

@@ -426,7 +426,7 @@ impl<T, A: Allocator + Clone> RawTable<T, A> {
     /// leave the data pointer dangling since that bucket is never written to
     /// due to our load factor forcing us to always have at least 1 free bucket.
     #[inline]
-    pub fn new_in(alloc: A) -> Self {
+    pub const fn new_in(alloc: A) -> Self {
         Self {
             table: RawTableInner::new_in(alloc),
             marker: PhantomData,

src/set.rs

@@ -387,7 +387,8 @@ impl<T, S> HashSet<T, S, Global> {
     /// Creates a new empty hash set which will use the given hasher to hash
     /// keys.
     ///
-    /// The hash set is also created with the default initial capacity.
+    /// The hash set is initially created with a capacity of 0, so it will not
+    /// allocate until it is first inserted into.
     ///
     /// Warning: `hasher` is normally randomly generated, and
     /// is designed to allow `HashSet`s to be resistant to attacks that
@@ -464,7 +465,8 @@ where
     /// Creates a new empty hash set which will use the given hasher to hash
     /// keys.
     ///
-    /// The hash set is also created with the default initial capacity.
+    /// The hash set is initially created with a capacity of 0, so it will not
+    /// allocate until it is first inserted into.
     ///
     /// Warning: `hasher` is normally randomly generated, and
     /// is designed to allow `HashSet`s to be resistant to attacks that
@@ -482,7 +484,7 @@ where
     /// set.insert(2);
     /// ```
     #[cfg_attr(feature = "inline-more", inline)]
-    pub fn with_hasher_in(hasher: S, alloc: A) -> Self {
+    pub const fn with_hasher_in(hasher: S, alloc: A) -> Self {
         Self {
             map: HashMap::with_hasher_in(hasher, alloc),
         }