#import <coobjc.h>写入pch文件导致编译失败

### Environment Details

* coobjc version:1.2.0
* iOS version:13.2.3
* Xcode version:10.3
* Other informations:

### Expected behavior
编译通过

### Actual behavior
在多处类似 [obj objectAtIndex:indexPath.row] 的地方出现错误：
Multiple methods named 'objectAtIndex:' found with mismatched result, parameter type or attributes

### Steps to Reproduce
#import 写入pch文件

Reproduce the failure on coobjc 1.2.0 with iOS 13.2.3 and Xcode 10.3 by placing #import in the PCH. Trace the objectAtIndex: call sites reporting mismatched methods and verify that the project compiles successfully after the issue is addressed.

Written by the indexing model from the issue text.