feat: add fish-lsp support (#3188)

lua/lspconfig/server_configurations/fish_lsp.lua

@@ -0,0 +1,26 @@
+local util = require 'lspconfig.util'
+
+return {
+  default_config = {
+    cmd = { 'fish-lsp', 'start' },
+    cmd_env = { fish_lsp_show_client_popups = false },
+    filetypes = { 'fish' },
+    root_dir = util.find_git_ancestor,
+    single_file_support = true,
+  },
+  docs = {
+    description = [[
+https://github.com/ndonfris/fish-lsp
+
+A Language Server Protocol (LSP) tailored for the fish shell.
+This project aims to enhance the coding experience for fish,
+by introducing a suite of intelligent features like auto-completion,
+scope aware symbol analysis, per-token hover generation, and many others.
+
+[homepage](https://www.fish-lsp.dev/)
+]],
+    default_config = {
+      root_dir = [[util.find_git_ancestor]],
+    },
+  },
+}