docs: Update Ruby docs to provide more complete examples (#17987)

Closes #17917

Release Notes:

- N/A

docs/src/languages/ruby.md

@@ -138,15 +138,21 @@ Ruby LSP uses pull-based diagnostics which Zed doesn't support yet. We can tell
 
 ```json
 {
+  "languages": {
+    "Ruby": {
+      "language_servers": ["ruby-lsp", "!solargraph", "..."],
+    },
+  },
   "lsp": {
     "ruby-lsp": {
       "initialization_options": {
         "enabledFeatures": {
-          "diagnostics": false
-        }
-      }
-    }
-  }
+          // This disables diagnostics
+          "diagnostics": false,
+        },
+      },
+    },
+  },
 }
 ```
 
@@ -164,11 +170,24 @@ Rubocop has unsafe autocorrection disabled by default. We can tell Zed to enable
 
 ```json
 {
+  "languages": {
+    "Ruby": {
+      // Use ruby-lsp as the primary language server and rubocop as the secondary.
+      "language_servers": ["ruby-lsp", "rubocop", "!solargraph", "..."]
+    }
+  },
   "lsp": {
     "rubocop": {
       "initialization_options": {
         "safeAutocorrect": false
       }
+    },
+    "ruby-lsp": {
+      "initialization_options": {
+        "enabledFeatures": {
+          "diagnostics": false
+        }
+      }
     }
   }
 }