Add minimal snippets documentation (#14992)

Release Notes:

- N/A

docs/src/snippets.md

@@ -0,0 +1,32 @@
+# Snippets
+
+Place your snippet files in `~/.config/zed/snippets` directory.
+
+Ex: If you want to create snippets that targeted JavaScript files, your file would be `javascript.json` and it might contain:
+
+```json
+{
+  "Log to the console": {
+    "prefix": "log",
+    "body": ["console.log($1);", "$0"],
+    "description": "Log to the console"
+  },
+  "Log warning to console": {
+    "prefix": "warn",
+    "body": ["console.warn($1);", "$0"],
+    "description": "Log warning to the console"
+  },
+  "Log error to console": {
+    "prefix": "error",
+    "body": ["console.error($1);", "$0"],
+    "description": "Log error to the console"
+  },
+  "Throw Exception": {
+    "prefix": "throw",
+    "body": ["throw new Error(\"$1\");", "$0"],
+    "description": "Throw Exception"
+  }
+}
+```
+
+For more configuration information, see the [`simple-completion-language-server` instructions](https://github.com/zed-industries/simple-completion-language-server/tree/main).