Make GetAsync protected internal so external inheritors can override it

Author: alec-petersen

modules/openapi-generator/src/main/resources/csharp/libraries/generichost/RateLimitProvider`1.mustache

@@ -85,7 +85,8 @@ namespace {{packageName}}.{{clientPackage}}
                 }
         }
 
-        internal override async System.Threading.Tasks.ValueTask<TTokenBase> GetAsync(string header = "", System.Threading.CancellationToken cancellation = default{{^netstandard20OrLater}}(global::System.Threading.CancellationToken){{/netstandard20OrLater}})
+        /// <inheritdoc/>
+        protected internal override async System.Threading.Tasks.ValueTask<TTokenBase> GetAsync(string header = "", System.Threading.CancellationToken cancellation = default{{^netstandard20OrLater}}(global::System.Threading.CancellationToken){{/netstandard20OrLater}})
         {
             if (!AvailableTokens.TryGetValue(header, out global::System.Threading.Channels.Channel<TTokenBase>{{nrt?}} tokens))
                 throw new KeyNotFoundException($"Could not locate a token for header '{header}'.");

modules/openapi-generator/src/main/resources/csharp/libraries/generichost/TokenProvider`1.mustache

@@ -22,7 +22,12 @@ namespace {{packageName}}
         /// </summary>
         protected TTokenBase[] _tokens;
 
-        internal abstract System.Threading.Tasks.ValueTask<TTokenBase> GetAsync(string header = "", System.Threading.CancellationToken cancellation = default{{^netstandard20OrLater}}(global::System.Threading.CancellationToken){{/netstandard20OrLater}});
+        /// <summary>
+        /// Gets an authentication token to be used in request authorization.
+        /// </summary>
+        /// <param name="header"></param>
+        /// <param name="cancellation"></param>
+        protected internal abstract System.Threading.Tasks.ValueTask<TTokenBase> GetAsync(string header = "", System.Threading.CancellationToken cancellation = default{{^netstandard20OrLater}}(global::System.Threading.CancellationToken){{/netstandard20OrLater}});
 
         /// <summary>
         /// Instantiates a TokenProvider.