Add a bunch of doc comments

We get a lot of build output because of missing XML comments that we
ignore. I'd like to stop ignoring them. To do that, we need to doc the
💩 out of everything.

Octokit/Models/Request/UpdateTeam.cs

@@ -4,14 +4,26 @@ using System.Globalization;
 
 namespace Octokit
 {
+    /// <summary>
+    /// Used to update a teamm.
+    /// </summary>
     [DebuggerDisplay("{DebuggerDisplay,nq}")]
     public class UpdateTeam
     {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="UpdateTeam"/> class.
+        /// </summary>
+        /// <param name="team">The team.</param>
         public UpdateTeam(string team)
         {
             Name = team;
         }
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="UpdateTeam"/> class.
+        /// </summary>
+        /// <param name="team">The team.</param>
+        /// <param name="permission">The permission.</param>
         public UpdateTeam(string team, Permission permission)
         {
             Name = team;