message: Fix typo in FAQ
  "an" -> "a"
diff: @@ -43,5 +43,5 @@ Will CMake Tools Ever Support ``<XYZ>``?
  ****************************************
  Only if you voice support for it as a `GitHub issue
  -<https://github.com/vector-of-bool/vscode-cmake-tools/issues>`_. Open an feature
  +<https://github.com/vector-of-bool/vscode-cmake-tools/issues>`_. Open a feature
  request or search for and provide feedback for an existing one!
  