VSCode: Don't trim tailing whitespace in markdown

In some version, VSCode was so crazy to trim trailing whitespac in
markdown as well. But there, it actually has a meaning.

files/vscode-settings.json

@@ -36,6 +36,9 @@
         "editor.formatOnSave": false,
         "editor.wordWrap": "on"
     },
+    "[markdown]": {
+        "files.trimTrailingWhitespace": false
+    },
     "python.linting.pylintPath": "/usr/local/bin/pylint",
     "python.pythonPath": "/usr/local/bin/python3",
     "window.zoomLevel": 0,