rtags: add :emacs recommended requirement

minimum version set to upstream recommendation

Closes #21738.

Signed-off-by: ilovezfs <ilovezfs@icloud.com>

Formula/rtags.rb

@@ -4,6 +4,8 @@ class Rtags < Formula
   url "https://github.com/Andersbakken/rtags.git",
       :tag => "v2.16",
       :revision => "8ef7554852541eced514c56d5e39d6073f7a2ef9"
+  revision 1
+
   head "https://github.com/Andersbakken/rtags.git"
 
   bottle do
@@ -16,6 +18,8 @@ class Rtags < Formula
   depends_on "llvm"
   depends_on "openssl"
 
+  depends_on :emacs => ["24.3", :recommended]
+
   def install
     # Homebrew llvm libc++.dylib doesn't correctly reexport libc++abi
     ENV.append("LDFLAGS", "-lc++abi")