docs: Minor typo in tutorial.rst

Author: mcclure

docs/tutorial.rst

@@ -8,4 +8,4 @@ Tutorial
       * `Learning FPGA Design with nMigen <https://vivonomicon.com/2020/04/14/learning-fpga-design-with-nmigen/>`_ by Vivonomicon;
       * `"I want to learn nMigen" <https://github.com/kbob/nmigen-examples>`_ by kbob;
       * `A tutorial for using Amaranth HDL <https://github.com/robertbaruch/amaranth-tutorial>`_ by Robert Baruch.
-      * `Graded exeercises for Amaranth HDL <https://github.com/robertbaruch/amaranth-exercises>`_ by Robert Baruch.
+      * `Graded exercises for Amaranth HDL <https://github.com/robertbaruch/amaranth-exercises>`_ by Robert Baruch.