CRLF terminate get-pure-port/headers; fixes #1901

Supply a final CRLF just like purify-port.

pkgs/net-test/tests/net/url-port.rkt

@@ -102,25 +102,25 @@
     "HTTP/1.1 200 OK\r\nContent-Type: text/plain\r\nTransfer-Encoding: chunked\r\n\r\n24\r\nThis is the data in the first chunk \r\n1A\r\nand this is the second one\r\n0\r\n")
    =>
    (values "This is the data in the first chunk and this is the second one"
-           "Content-Type: text/plain\r\nTransfer-Encoding: chunked\r\n")
+           "Content-Type: text/plain\r\nTransfer-Encoding: chunked\r\n\r\n")
 
    (get-pure/headers
     "HTTP/1.0 200 OK\r\nContent-Type: text/plain\r\n\r\nThis is the data in the first chunk and this is the second one")
    =>
    (values "This is the data in the first chunk and this is the second one"
-           "Content-Type: text/plain\r\n")
+           "Content-Type: text/plain\r\n\r\n")
 
    (get-pure/headers
     "HTTP/1.1 200 OK\r\nContent-Type: text/plain\r\nTransfer-Encoding: chunked\r\n\r\n20\r\nThis is the data in the first ch\r\n21\r\nand this is the second oneXXXXXXX\r\n0\r\n")
    =>
    (values "This is the data in the first chand this is the second oneXXXXXXX"
-           "Content-Type: text/plain\r\nTransfer-Encoding: chunked\r\n")
+           "Content-Type: text/plain\r\nTransfer-Encoding: chunked\r\n\r\n")
 
    (get-pure/headers
     "HTTP/1.1 200 OK\r\nContent-Type: text/plain\r\nTransfer-Encoding: chunked\r\nAnother-Header: ta-daa\r\n\r\n20\r\nThis is the data in the first ch\r\n21\r\nand this is the second oneXXXXXXX\r\n0\r\n")
    =>
    (values "This is the data in the first chand this is the second oneXXXXXXX"
-           "Content-Type: text/plain\r\nTransfer-Encoding: chunked\r\nAnother-Header: ta-daa\r\n")
+           "Content-Type: text/plain\r\nTransfer-Encoding: chunked\r\nAnother-Header: ta-daa\r\n\r\n")
    )
 
   (unless skip-actual-redirect?
@@ -135,7 +135,7 @@
       "HTTP/1.1 200 OK\r\nContent-Type: text/plain\r\nTransfer-Encoding: chunked\r\nAnother-Header: ta-daa\r\n\r\n20\r\nThis is the data in the first ch\r\n21\r\nand this is the second oneXXXXXXX\r\n0\r\n")
      =>
      (values "This is the data in the first chand this is the second oneXXXXXXX"
-             "Content-Type: text/plain\r\nTransfer-Encoding: chunked\r\nAnother-Header: ta-daa\r\n")))
+             "Content-Type: text/plain\r\nTransfer-Encoding: chunked\r\nAnother-Header: ta-daa\r\n\r\n")))
 
   (test
    (put-pure

racket/collects/net/url.rkt

@@ -338,11 +338,12 @@
        (redirection-loop (- redirections 1) new-url #f)]
       [else
        (values response-port
-               (apply string-append
-                      (map (λ (x) (format "~a\r\n" x))
-                           (if status?
-                             (cons status headers)
-                             headers))))])))
+               (string-append (apply string-append
+                                     (map (λ (x) (format "~a\r\n" x))
+                                          (if status?
+                                              (cons status headers)
+                                              headers)))
+                              "\r\n"))])))
 
 ;; get-pure-port : url [x list (str)] -> in-port
 (define (get-pure-port url [strings '()] #:redirections [redirections 0])