Update HttpBasics_ProxyIntro0.adoc

Fixed typo, Actual : "wihtin" , Expected :  "within"

webgoat-lessons/http-proxies/src/main/resources/lessonPlans/en/HttpBasics_ProxyIntro0.adoc

@@ -2,7 +2,7 @@
 == HTTP Proxy Overview
 
 Many times proxies are used as a way of accessing otherwise blocked content.  A user might connect to server A, which relays content from server B
- ... Because Server B is blocked wihtin the user's network. That's not the use case we will be dealing with here, but the concept is the same.
+ ... Because Server B is blocked within the user's network. That's not the use case we will be dealing with here, but the concept is the same.
 HTTP Proxies receive requests from a client and relay them. They also typically record them. They act as a man-in-the-middle (keep that in mind if you decide to
 use a proxy server to connect to some other system that is otherwise blocked). We won't get into HTTP vs HTTPS just yet, but that's an important topic in
 relationship to proxies.