[7.4] 2e92db9fc man: Fix the scope of beresp protected headers

[Dridi Boukelmoune]

commit 2e92db9fcb9c3f3cab11498179cabd6722e19540
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Tue Sep 19 06:22:48 2023 +0200

    man: Fix the scope of beresp protected headers
    
    Refs #3984

diff --git a/doc/sphinx/reference/vcl_var.rst b/doc/sphinx/reference/vcl_var.rst
index b9b74f0e3..392e3efe7 100644
--- a/doc/sphinx/reference/vcl_var.rst
+++ b/doc/sphinx/reference/vcl_var.rst
@@ -1164,7 +1164,7 @@ beresp.http.content-length
 
 	Type: HEADER
 
-	Readable from: client
+	Readable from: vcl_backend_response, vcl_backend_error
 
 	The content-length header field is protected, see protected_headers_.
 
@@ -1173,7 +1173,7 @@ beresp.http.transfer-encoding
 
 	Type: HEADER
 
-	Readable from: client
+	Readable from: vcl_backend_response, vcl_backend_error
 
 	The transfer-encoding header field is protected, see protected_headers_.