feat(优化代码): 优化配置读写，修复边界问题

goini.go

@@ -152,7 +152,7 @@ func (ini *GoINI) SetString(name string, key string, value string) {
 	if index, ok := ini.findSectionKeyLineIndex(name, key); ok {
 		ini.fileLines[index].keyValue = value
 		ini.fileLines[index].modified = true
-		ini.rebuildIndexes()
+		ini.sectionValues[name][key] = value
 		return
 	}
 	ini.ensureSectionLine(name)