feat: add anakin language server (Python) (#2217)

* feat: add anakin-language-server

* fix(anakin-language-server): use the correct executable name

* fix(anakin-language-server): display errors as ERROR, not WARNING

This is an attempt to elevate the reporting level of mistakes that will
cause you program to crash unexpectedly, above the level of style
warnings and other non-critical problems.

* fix(anakin-language-server): style warning

1 files changed, 78 insertions, 0 deletions

diff --git a/lua/lspconfig/server_configurations/anakin_language_server.lua b/lua/lspconfig/server_configurations/anakin_language_server.lua
new file mode 100644
index 00000000..f0c281cc
--- /dev/null
+++ b/lua/lspconfig/server_configurations/anakin_language_server.lua
@@ -0,0 +1,78 @@
+local util = require 'lspconfig.util'
+
+return {
+  default_config = {
+    cmd = { 'anakinls' },
+    filetypes = { 'python' },
+    root_dir = function(fname)
+      local root_files = {
+        'pyproject.toml',
+        'setup.py',
+        'setup.cfg',
+        'requirements.txt',
+        'Pipfile',
+      }
+      return util.root_pattern(unpack(root_files))(fname) or util.find_git_ancestor(fname)
+    end,
+    single_file_support = true,
+    settings = {
+      anakinls = {
+        pyflakes_errors = {
+          -- Full list: https://github.com/PyCQA/pyflakes/blob/master/pyflakes/messages.py
+
+          'ImportStarNotPermitted',
+
+          'UndefinedExport',
+          'UndefinedLocal',
+          'UndefinedName',
+
+          'DuplicateArgument',
+          'MultiValueRepeatedKeyLiteral',
+          'MultiValueRepeatedKeyVariable',
+
+          'FutureFeatureNotDefined',
+          'LateFutureImport',
+
+          'ReturnOutsideFunction',
+          'YieldOutsideFunction',
+          'ContinueOutsideLoop',
+          'BreakOutsideLoop',
+
+          'TwoStarredExpressions',
+          'TooManyExpressionsInStarredAssignment',
+
+          'ForwardAnnotationSyntaxError',
+          'RaiseNotImplemented',
+
+          'StringDotFormatExtraPositionalArguments',
+          'StringDotFormatExtraNamedArguments',
+          'StringDotFormatMissingArgument',
+          'StringDotFormatMixingAutomatic',
+          'StringDotFormatInvalidFormat',
+
+          'PercentFormatInvalidFormat',
+          'PercentFormatMixedPositionalAndNamed',
+          'PercentFormatUnsupportedFormat',
+          'PercentFormatPositionalCountMismatch',
+          'PercentFormatExtraNamedArguments',
+          'PercentFormatMissingArgument',
+          'PercentFormatExpectedMapping',
+          'PercentFormatExpectedSequence',
+          'PercentFormatStarRequiresSequence',
+        },
+      },
+    },
+  },
+  docs = {
+    description = [[
+https://pypi.org/project/anakin-language-server/
+
+`anakin-language-server` is yet another Jedi Python language server.
+
+Available options:
+
+* Initialization: https://github.com/muffinmad/anakin-language-server#initialization-option
+* Configuration: https://github.com/muffinmad/anakin-language-server#configuration-options
+    ]],
+  },
+}