docs: Fix name for net.ipv4.udp_child_hash_entries

udp_child_ehash_entries -> udp_child_hash_entries

Fixes: 9804985 ("udp: Introduce optional per-netns hash table.")
Signed-off-by: Jordan Rife <jordan@jrife.io>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250808185800.1189042-1-jordan@jrife.io
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: jrife

Documentation/networking/ip-sysctl.rst

@@ -1420,7 +1420,7 @@ udp_hash_entries - INTEGER
 	A negative value means the networking namespace does not own its
 	hash buckets and shares the initial networking namespace's one.
 
-udp_child_ehash_entries - INTEGER
+udp_child_hash_entries - INTEGER
 	Control the number of hash buckets for UDP sockets in the child
 	networking namespace, which must be set before clone() or unshare().