doc: use example.com for examples

PR-URL: #41827
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Beth Griggs <bgriggs@redhat.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Mestery <mestery@protonmail.com>

doc/api/http.md

@@ -22,7 +22,7 @@ HTTP message headers are represented by an object like this:
 { 'content-length': '123',
   'content-type': 'text/plain',
   'connection': 'keep-alive',
-  'host': 'mysite.com',
+  'host': 'example.com',
   'accept': '*/*' }
 ```
 
@@ -47,7 +47,7 @@ list like the following:
   'content-LENGTH', '123',
   'content-type', 'text/plain',
   'CONNECTION', 'keep-alive',
-  'Host', 'mysite.com',
+  'Host', 'example.com',
   'accepT', '*/*' ]
 ```