vsftpd: fix RuboCop Style/TrailingBodyOnMethodDefinition.

Formula/vsftpd.rb

@@ -35,7 +35,8 @@ class Vsftpd < Formula
     man8.install "vsftpd.8"
   end
 
-  def caveats; <<~EOS
+  def caveats
+    <<~EOS
       To use chroot, vsftpd requires root privileges, so you will need to run
       `sudo vsftpd`.
       You should be certain that you trust any software you grant root privileges.
@@ -47,7 +48,8 @@ class Vsftpd < Formula
 
   plist_options :startup => true, :manual => "sudo vsftpd"
 
-  def plist; <<~EOS
+  def plist
+    <<~EOS
       <?xml version="1.0" encoding="UTF-8"?>
       <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
       <plist version="1.0">