docs: fix the demo code fence and list markdown() in the method table

The demo block opened as ```javapublic, fusing the fence and the first
line of code, so the block was tagged with a bogus "javapublic" language
and lost its highlighting. The stray "public" was not in the source
either: demo App is declared "class App", package-private.

markdown() was also absent from the migration table, which is the
closest thing the README has to a list of the client's methods.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: jvmvik

README.md

@@ -43,7 +43,7 @@ make all SERPAPI_KEY='<your private key>'
 Use quotes if your key contains shell-special characters. You need a SerpApi account to obtain a key: https://serpapi.com/dashboard
 
 `demo/src/main/java/demo/App.java`:
-```javapublic 
+```java
 class App {
     public static void main(String[] args) {
         String apiKey = System.getenv("SERPAPI_KEY");
@@ -577,6 +577,7 @@ implementation 'com.github.serpapi:serpapi-java:1.2.0'
 | `SerpApiSearch` | `SerpApi` |
 | `client.getJson()` | `client.search(parameter)` |
 | `client.getHtml()` | `client.html(parameter)` |
+| — | `client.markdown(parameter)` — new in 1.2.0, see [Markdown output](#markdown-output) |
 | `client.getSearchArchive(id)` | `client.searchArchive(id)` |
 | `client.getAccount()` | `client.account()` |
 | `client.getLocation(parameter)` | `client.location(parameter)` |

README.md.erb

@@ -65,7 +65,7 @@ make all SERPAPI_KEY='<your private key>'
 Use quotes if your key contains shell-special characters. You need a SerpApi account to obtain a key: https://serpapi.com/dashboard
 
 `demo/src/main/java/demo/App.java`:
-```javapublic 
+```java
 class App {
     public static void main(String[] args) {
         String apiKey = System.getenv("SERPAPI_KEY");
@@ -318,6 +318,7 @@ implementation 'com.github.serpapi:serpapi-java:1.2.0'
 | `SerpApiSearch` | `SerpApi` |
 | `client.getJson()` | `client.search(parameter)` |
 | `client.getHtml()` | `client.html(parameter)` |
+| — | `client.markdown(parameter)` — new in 1.2.0, see [Markdown output](#markdown-output) |
 | `client.getSearchArchive(id)` | `client.searchArchive(id)` |
 | `client.getAccount()` | `client.account()` |
 | `client.getLocation(parameter)` | `client.location(parameter)` |