[xdoctest][task 355] reformat example code with google style in pir.cc

[DrRyanHuang]

PR types

Others

PR changes

Others

Description

修改如下文件的示例代码，使其通过 xdoctest 检查：

paddle/fluid/pybind/pir.cc

Related links

• [xdoctest] 分批次修改已有代码的示例 #55629
• [Add] Paddle 代码 CI 中引入 xdoctest 检查 #55295

由于目前需要等待 #56550 合入(我这俩天尽快搞定😭)(已合入)
后 2/3 的doc才可以修改，先把pr放上来

目前发现依旧存在该问题

Input [x] of op [elementwise_add] not found in param map
可能是 op_translator.cc 映射的问题，待排查

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[paddle-ci-bot]

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[DrRyanHuang]

第 3 批最后一个任务? 🤣🤣🤣

2023-10-31 07:13:38 **************************************************************
2023-10-31 07:13:38 Please find RD for approval first, and then find TPM for approval.
2023-10-31 07:13:38 0. print or std::cout is not recommended for direct use, please use logging or VLOG. If it is necessary to use, please contact tianshuo78520a (Recommend) or zhangbo9674 review and approve.
2023-10-31 07:13:38 
2023-10-31 07:13:38 There are 1 approved errors.
2023-10-31 07:13:38 **************************************************************

[SigureMo]

变量名里的 new_ir 改成 pir 吧，有些不能改的地方不用改

[SigureMo]

LGTMeow