Documents header usage with help

Author: joncloud

README.md

@@ -41,6 +41,10 @@ Options:
 Content:
 Repeat as many content arguments to create content sent with the HTTP request. Alternatively pipe raw content send as the HTTP request content.
   <KEY>=<VALUE>
+
+Headers:
+Repeat as many header arguments to assign headers for the HTTP request.
+  <KEY>:<VALUE>
 ```
 
 For example `https put httpbin.org/put hello=world` will output:

src/https/Program.cs

@@ -159,6 +159,10 @@ void Help()
             writer.WriteLine("Repeat as many content arguments to create content sent with the HTTP request. Alternatively pipe raw content send as the HTTP request content.");
             writer.WriteLine("  <KEY>=<VALUE>");
             writer.WriteLine("");
+            writer.WriteLine("Headers:");
+            writer.WriteLine("Repeat as many header arguments to assign headers for the HTTP request.");
+            writer.WriteLine("  <KEY>:<VALUE>");
+            writer.WriteLine("");
 
             writer.Flush();
         }