Switch manual shader dispose to using statement

hexworld/HexRender.cs

@@ -33,9 +33,10 @@ namespace hexworld
         {
             base.OnLoad(e);
 
-            var vs = Shader.FromFile("res/direct.vs.glsl");
-            var red = Shader.FromFile("res/red.fs.glsl");
-            var white = Shader.FromFile("res/white.fs.glsl");
+            using (var vs = Shader.FromFile("res/direct.vs.glsl"))
+            using (var red = Shader.FromFile("res/red.fs.glsl"))
+            using (var white = Shader.FromFile("res/white.fs.glsl"))
+            {
                 _whitePgm = Program.FromShaders(vs, red);
                 _redPgm = Program.FromShaders(vs, white);
 
@@ -67,10 +68,7 @@ namespace hexworld
                 Buffer.ArrayBuffer = _recVbo;
                 GL.EnableVertexAttribArray(0);
                 GL.VertexAttribPointer(0, 2, VertexAttribPointerType.Float, false, 0, 0);
-
-            vs?.Dispose();
-            red?.Dispose();
-            white?.Dispose();
+            }
         }
 
         /// <inheritdoc />