fix

Author: Snawoot

README.md

@@ -194,7 +194,7 @@ It is possible to filter (allow or deny) requests with simple `access` JS functi
    * **proto** *(String)* - the protocol version for incoming server requests.
    * **protoMajor** *(Number)* - numeric major protocol version.
    * **protoMinor** *(Number)* - numeric minor protocol version.
-   * **header** *(Object)* - mapping of *String* headers (except Host) in canonical form to *Array* of their *String* values.
+   * **header** *(Object)* - mapping of *String* headers (except Host) in canonical form to an *Array* of their *String* values.
    * **contentLength** *(Number)* - length of request body, if known.
    * **transferEncoding** *(Array)* - lists the request's transfer encodings from outermost to innermost.
    * **host** *(String)* - specifies the host on which the URL is sought. For HTTP/1 (per RFC 7230, section 5.4), this is either the value of the "Host" header or the host name given in the URL itself. For HTTP/2, it is the value of the ":authority" pseudo-header field.