docs: Validate JSON snippets (settings, keymap, tasks, etc) (#40043)

Closes #ISSUE

Release Notes:

- N/A *or* Added/Fixed/Improved ...

docs/src/languages/haskell.md

@@ -19,7 +19,7 @@ which haskell-language-server-wrapper
 
 If you need to configure haskell-language-server (hls) you can add configuration options to your Zed settings.json:
 
-```json
+```json [settings]
 {
   "lsp": {
     "hls": {
@@ -37,7 +37,7 @@ See the official [configuring haskell-language-server](https://haskell-language-
 
 If you would like to use a specific hls binary, or perhaps use [static-ls](https://github.com/josephsumabat/static-ls) as a drop-in replacement instead, you can specify the binary path and arguments:
 
-```json
+```json [settings]
 {
   "lsp": {
     "hls": {