Close #2472 - Add support for pyright

doc/ale-python.txt

@@ -598,6 +598,7 @@ g:ale_python_pylint_use_msg_id                 *g:ale_python_pylint_use_msg_id*
   Use message for output (e.g. I0011) instead of symbolic name of the message
   (e.g. locally-disabled).
 
+
 ===============================================================================
 pyls                                                          *ale-python-pyls*
 
@@ -682,6 +683,65 @@ g:ale_python_pyre_auto_pipenv                   *g:ale_python_pyre_auto_pipenv*
   if true. This is overridden by a manually-set executable.
 
 
+===============================================================================
+pyright                                                    *ale-python-pyright*
+
+The `pyrlight` linter requires a recent version of `pyright` which includes
+the `pyright-langserver` executable. You can install `pyright` on your system
+through `npm` with `sudo npm install -g pyright` or similar.
+
+Refer to their README for installation instructions:
+https://github.com/Microsoft/pyright
+
+`pyright` needs to know the path to your Python executable and probably a
+virtualenv to run. ALE will try to detect these automatically.
+See |g:ale_python_pyright_config|.
+
+
+g:ale_python_pyright_executable               *g:ale_python_pyright_executable*
+                                              *b:ale_python_pyright_executable*
+  Type: |String|
+  Default: `'pyright-langserver'`
+
+  The executable for running `pyright`, which is typically installed globally.
+
+
+g:ale_python_pyright_config                       *g:ale_python_pyright_config*
+                                                  *b:ale_python_pyright_config*
+  Type: |Dictionary|
+  Default: `{}`
+
+  Settings for configuring the `pyright` language server.
+
+  See pyright's documentation for a full list of options:
+  https://github.com/microsoft/pyright/blob/master/docs/settings.md
+
+  ALE will automatically try to set defaults for `venvPath` and `pythonPath`
+  so your project can automatically be checked with the right libraries.
+  You can override these settings with whatever you want in your ftplugin
+  file like so: >
+
+  let b:ale_python_pyright_config = {
+  \ 'python': {
+  \   'pythonPath': '/bin/python',
+  \   'venvPath': '/other/dir',
+  \ },
+  \}
+<
+  If `venvPath` is set, but `pythonPath` is not,
+  ALE will use `venvPath . '/bin/python'` or similar as `pythonPath`.
+
+  A commonly used setting for `pyright` is disabling language services
+  apart from type checking and "hover" (|ale-hover|), you can set this
+  setting like so, or use whatever other settings you want: >
+
+  let b:ale_python_pyright_config = {
+  \ 'pyright': {
+  \   'disableLanguageServices': v:true,
+  \ },
+  \}
+<
+
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 reorder-python-imports                      *ale-python-reorder_python_imports*