docs: set recommended JVM heap to -Xms2g -Xmx9g

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Little-Peony

docs/modular-deployment-en.md

@@ -46,8 +46,8 @@ java-tron-1.0.0/bin/FullNode -c config.conf -w
 JVM options can also be specified, located in `bin/java-tron.vmoptions`:
 ```
 # demo (compatible with JDK 8 / JDK 17)
--Xms256m
--Xmx4g
+-Xms2g
+-Xmx9g
 -XX:+PrintGCDetails
 -Xloggc:./gc.log
 -XX:+PrintGCDateStamps

docs/modular-deployment-zh.md

@@ -44,8 +44,8 @@ java-tron-1.0.0/bin/FullNode -c config.conf -w
 java-tron 支持对 jvm 参数进行配置，配置文件为 bin 目录下的 java-tron.vmoptions 文件。
 ```
 # demo（兼容 JDK 8 / JDK 17）
--Xms256m
--Xmx4g
+-Xms2g
+-Xmx9g
 -XX:+PrintGCDetails
 -Xloggc:./gc.log
 -XX:+PrintGCDateStamps