Fix spelling error and introduce Stockfish 11 instead of Stockfish 10

.travis.yml

@@ -17,10 +17,10 @@ before_cache:
  - rm -f data/syzygy/suicide/travis_wait_*.log || true
 before_install:
  - | # Stockfish
-     wget https://stockfish.s3.amazonaws.com/stockfish-10-linux.zip
-     unzip stockfish-10-linux.zip
+     wget https://stockfish.s3.amazonaws.com/stockfish-11-linux.zip
+     unzip stockfish-11-linux.zip
      mkdir -p bin
-     cp stockfish-10-linux/Linux/stockfish_10_x64_modern bin/stockfish
+     cp stockfish-11-linux/Linux/stockfish_20011801_x64_bmi2 bin/stockfish
      chmod +x bin/stockfish
      export PATH="`pwd`/bin:${PATH}"
      which stockfish || (echo $PATH && false)

appveyor.yml

@@ -8,9 +8,9 @@ build: off
 
 install:
   # Stockfish
-  - ps: Start-FileDownload "https://stockfishchess.org/files/stockfish-10-win.zip"
-  - 7z e stockfish-10-win.zip stockfish-10-win/Windows/*.exe
-  - ren stockfish_10_x64_popcnt.exe stockfish.exe
+  - ps: Start-FileDownload "https://stockfishchess.org/files/stockfish-11-win.zip"
+  - 7z e stockfish-11-win.zip stockfish-11-win/Windows/*.exe
+  - ren stockfish_20011801_x64_bmi2.exe stockfish.exe
   - set PATH=%cd%;%PATH%
 
 test_script:

docs/engine.rst

@@ -279,7 +279,7 @@ Example: Stream information from the engine and stop on an arbitrary condition.
     .. py:attribute:: move
         :type: Optional[chess.Move]
 
-        The best move accordig to the engine, or ``None``.
+        The best move according to the engine, or ``None``.
 
     .. py:attribute:: ponder
         :type: Optional[chess.Move]