Rollup merge of #86852 - Amanieu:remove_doc_aliases, r=joshtriplett

Remove some doc aliases

As per the new doc alias policy in https://github.com/rust-lang/std-dev-guide/pull/25, this removes some controversial doc aliases:
- `malloc`, `alloc`, `realloc`, etc.
- `length` (alias for `len`)
- `delete` (alias for `remove` in collections and also file/directory deletion)

r? `@joshtriplett`

library/core/src/iter/traits/exact_size.rs

@@ -97,7 +97,6 @@ pub trait ExactSizeIterator: Iterator {
     ///
     /// assert_eq!(5, five.len());
     /// ```
-    #[doc(alias = "length")]
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn len(&self) -> usize {

library/core/src/slice/mod.rs

@@ -95,7 +95,6 @@ impl<T> [T] {
     /// let a = [1, 2, 3];
     /// assert_eq!(a.len(), 3);
     /// ```
-    #[doc(alias = "length")]
     #[cfg_attr(not(bootstrap), lang = "slice_len_fn")]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_stable(feature = "const_slice_len", since = "1.39.0")]

library/core/src/str/mod.rs

@@ -138,7 +138,6 @@ impl str {
     /// assert_eq!("ƒoo".len(), 4); // fancy f!
     /// assert_eq!("ƒoo".chars().count(), 3);
     /// ```
-    #[doc(alias = "length")]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_stable(feature = "const_str_len", since = "1.39.0")]
     #[inline]