Removed spurious linebreak from new documentation

Author: ChaiTRex

library/alloc/src/collections/btree/map/entry.rs

@@ -118,7 +118,7 @@ impl<'a, K: Ord, V> Entry<'a, K, V> {
 
     /// Ensures a value is in the entry by inserting, if empty, the result of the default function.
     /// This method allows for generating key-derived values for insertion by providing the default
-    /// function a reference to the key that was moved during the `.entry(key)` method call.<br />
+    /// function a reference to the key that was moved during the `.entry(key)` method call.
     ///
     /// The reference to the moved key is provided so that cloning or copying the key is
     /// unnecessary, unlike with `.or_insert_with(|| ... )`.