update Chatops-Signature documentation to match implementation

Author: technoweenie

docs/protocol-description.md

@@ -172,16 +172,16 @@ string to be signed is:
 `https://example.com/_chatops\nabc123\n2017-05-11T19:15:23Z\n{"method": "foo"}`
 
 The signature header starts with the word `Signature`, followed by whitespace,
-followed by comma-separated key-value pairs separated by an `=`. Each
-value is closed with double quotes. Keys must be all lowercase.
+followed by comma-separated key-value pairs separated by an `=`. Keys must be
+all lowercase.
 
  * `keyid`: An implementation-specific key identifier that servers can use to
  determine which private key signed this request.
  * `signature`: The base64-encoded RSA-SHA256 signature of the signing string.
 
 An example signature header would be:
 
-`Chatops-Signature: Signature keyid="rsakey1",signature="<base64-encoded-signature>"`
+`Chatops-Signature: Signature keyid=rsakey1,signature=<base64-encoded-signature>`
 
 #### Authentication