Rename sshfs@2 to sshfs

GitHub currently mutates the `%` in URL-encoded filenames into `.`, thus breaking release downloads.

Also add some caveats.

Formula/sshfs.rb

@@ -1,6 +1,6 @@
 require_relative "../require/macfuse"
 
-class SshfsAT2 < Formula
+class Sshfs < Formula
   desc "File system client based on SSH File Transfer Protocol"
   homepage "https://github.com/libfuse/sshfs"
   url "https://github.com/libfuse/sshfs/archive/refs/tags/sshfs-2.10.tar.gz"
@@ -8,11 +8,6 @@ class SshfsAT2 < Formula
   license any_of: ["LGPL-2.1-only", "GPL-2.0-only"]
   revision 1
 
-  bottle do
-    root_url "https://github.com/gromgit/homebrew-fuse/releases/download/sshfs@2-2.10"
-    sha256 cellar: :any, big_sur: "553e89e48d2e1a12fb8cdbc7bcbf30571fce737dc4e8989ecc84ce3ae94a2c7d"
-  end
-
   depends_on "autoconf" => :build
   depends_on "automake" => :build
   depends_on "libtool" => :build
@@ -34,6 +29,16 @@ class SshfsAT2 < Formula
     system "make", "install"
   end
 
+  def caveats
+    <<~EOS
+      This formula is outdated, and is provided only as a courtesy.
+      It cannot be updated until MacFUSE supports FUSE API version 3.
+
+      If security issues are discovered with this old software,
+      it may be removed without notice.
+    EOS
+  end
+
   test do
     system "#{bin}/sshfs", "--version"
   end