Make edits_spec more robust

Author: alexrudall

spec/ruby/openai/client/edits_spec.rb

@@ -1,7 +1,7 @@
 RSpec.describe OpenAI::Client do
   describe "#edits", :vcr do
     let(:input) { "There are 7 days in a wek, and between 28 and 31 in a month." }
-    let(:instruction) { "Fix the spelling mistakes" }
+    let(:instruction) { "Fix the misspelled word 'week'" }
     let(:cassette) { "edits #{model} #{input}".downcase }
     let(:response) do
       OpenAI::Client.new.edits(