Fix a spelling mistake

Privileged was misspelled in the header comments.

Change-Id: Id91a16c26daa6813f373cdfd75c9aa84b400e9ce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3002222
Auto-Submit: Ali Beyad <abeyad@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Commit-Queue: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#897922}

services/network/public/cpp/parsed_headers.h

@@ -19,7 +19,7 @@ namespace network {
 // This function must remain:
 // - As 'pure' as possible. See [pure-function].
 // - Callable from any processes.
-//   For security reasons, highly proviledged processes must never call it
+//   For security reasons, highly privileged processes must never call it
 //   directly against untrustworthy inputs. See [rule-of-2]. In this case, you
 //   can call it indirectly via NetworkContext.ParseHeaders().
 //