search: split missing formula help into its own method

Library/Homebrew/cmd/search.rb

@@ -143,14 +143,21 @@ module Homebrew
 
     count = all_formulae.count + all_casks.count
 
-    if $stdout.tty? && (reason = MissingFormula.reason(query, silent: true)) && local_casks.exclude?(query)
+    print_missing_formula_help(query, count.positive?) if local_casks.exclude?(query)
-      if count.positive?
+
+    odie "No formulae or casks found for #{query.inspect}." if count.zero?
+  end
+
+  def print_missing_formula_help(query, found_matches)
+    return unless $stdout.tty?
+
+    reason = MissingFormula.reason(query, silent: true)
+    return if reason.nil?
+
+    if found_matches
       puts
       puts "If you meant #{query.inspect} specifically:"
     end
     puts reason
   end
-
-    odie "No formulae or casks found for #{query.inspect}." if count.zero?
-  end
 end