Fixed typo

Accidentally used " instead of ' in the `TrimEnd` function, which takes `params char[]`.

Author: ericBG

RedditSharp/Reddit.cs

@@ -210,7 +210,7 @@ public Subreddit GetSubreddit(string name)
                 name = name.Substring(2);
             if (name.StartsWith("/r/"))
                 name = name.Substring(3);
-            name = name.TrimEnd("/");
+            name = name.TrimEnd('/');
             return GetThing<Subreddit>(string.Format(SubredditAboutUrl, name));
         }
 
@@ -225,7 +225,7 @@ public async Task<Subreddit> GetSubredditAsync(string name)
                 name = name.Substring(2);
             if (name.StartsWith("/r/"))
                 name = name.Substring(3);
-            name = name.TrimEnd("/");
+            name = name.TrimEnd('/');
             return await GetThingAsync<Subreddit>(string.Format(SubredditAboutUrl, name));
         }