[docs] add gdscript missing docs

Author: ericdallo

docs/lsp-clients.json

@@ -153,6 +153,14 @@
     "installation-url": "https://github.com/saibing/bingo/wiki/Install",
     "debugger": "Yes"
   },
+  {
+    "name": "gdscript",
+    "full-name": "GDScript",
+    "server-name": "godot",
+    "server-url": "https://github.com/godotengine/godot",
+    "installation-url": "https://github.com/godotengine/godot",
+    "debugger": "Not available"
+  },
   {
     "name": "gopls",
     "full-name": "Go",

mkdocs.yml

@@ -41,6 +41,7 @@ nav:
     - Eslint: page/lsp-eslint.md
     - F#: page/lsp-fsharp.md
     - Fortran: page/lsp-fortran.md
+    - GDScript: page/lsp-gdscript.md
     - Go (gopls): page/lsp-gopls.md
     - Go (bingo): page/lsp-bingo.md
     - Groovy: page/lsp-groovy.md