feat: added harper_ls support

lua/lspconfig/server_configurations/harper_ls.lua

@@ -0,0 +1,22 @@
+local util = require 'lspconfig.util'
+
+return {
+  default_config = {
+    cmd = { 'harper-ls', '--stdio' },
+    filetypes = { 'markdown', 'rust', 'typescript', 'typescriptreact', 'javascript', 'python', 'go', 'c', 'cpp', 'ruby', 'swift', 'csharp', 'toml', 'lua' },
+    root_dir = util.find_git_ancestor,
+    single_file_support = true,
+    settings = {},
+  },
+  docs = {
+    description = [[
+https://github.com/chilipepperhott/harper_ls
+
+The language server for Harper, the slim, clean language checker for developers.
+As of right now, there are no settings to be configured for `harper_ls`.
+    ]],
+    default_config = {
+      root_dir = [[bufdir]],
+    },
+  },
+}