fix(drv_can): Suppress unused variable warning in send error path && docs(drv_gpio): Add detailed Doxygen comments for GET_PIN macro

[wdfk-prog]

拉取/合并请求描述：(PR description)

[

为什么提交这份PR (why to submit this PR)

1. 在 drv_can.c 驱动中，当发送邮箱被占用时，错误处理路径中存在一个已定义但未被使用的变量，这会在某些严格的编译环境下触发警告。
2. 在 drv_gpio.h 头文件中，核心的 GET_PIN 宏缺乏文档，开发者可能不清楚其具体作用、用法以及平台相关性，降低了代码的可维护性。

你的解决方案是什么 (what is your solution)

1. 修复 CAN 驱动警告：通过 (void)mailbox_mask; 语句，显式地将未使用的变量 mailbox_mask 转换为空类型，向编译器表明这是有意为之，从而消除编译警告。
2. 增强 GPIO 驱动文档：为 GET_PIN 宏添加了全面、详细的 Doxygen 风格注释。注释内容包括宏的功能描述、实现细节、参数说明、返回值、注意事项以及多个使用示例，极大地提升了代码的自文档化程度和易用性。

请提供验证的bsp和config (provide the config and bsp)

• BSP:

• .config:

• action:

]

当前拉取/合并请求的状态 Intent for your PR

必须选择一项 Choose one (Mandatory):

• 本拉取/合并请求是一个草稿版本 This PR is for a code-review and is intended to get feedback
• 本拉取/合并请求是一个成熟版本 This PR is mature, and ready to be integrated into the repo

代码质量 Code Quality：

我在这个拉取/合并请求中已经考虑了 As part of this pull request, I've considered the following:

• 已经仔细查看过代码改动的对比 Already check the difference between PR and old code
• 代码风格正确，包括缩进空格，命名及其他风格 Style guide is adhered to, including spacing, naming and other styles
• 没有垃圾代码，代码尽量精简，不包含#if 0代码，不包含已经被注释了的代码 All redundant code is removed and cleaned up
• 所有变更均有原因及合理的，并且不会影响到其他软件组件代码或BSP All modifications are justified and not affect other components or BSP
• 对难懂代码均提供对应的注释 I've commented appropriately where code is tricky
• 代码是高质量的 Code in this PR is of high quality
• 已经使用formatting 等源码格式化工具确保格式符合RT-Thread代码规范 This PR complies with RT-Thread code specification
• 如果是新增bsp, 已经添加ci检查到.github/ALL_BSP_COMPILE.json 详细请参考链接BSP自查

[github-actions]

👋 感谢您对 RT-Thread 的贡献！Thank you for your contribution to RT-Thread!

为确保代码符合 RT-Thread 的编码规范，请在你的仓库中执行以下步骤运行代码格式化工作流（如果格式化CI运行失败）。
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完成后，提交将自动更新至 stm32_can_and_gpio 分支，关联的 Pull Request 也会同步更新。
Once completed, commits will be pushed to the stm32_can_and_gpio branch automatically, and the related Pull Request will be updated.

如有问题欢迎联系我们，再次感谢您的贡献！💐
If you have any questions, feel free to reach out. Thanks again for your contribution!

[github-actions]

📌 Code Review Assignment

🏷️ Tag: bsp_stm32

Reviewers: @Liang1795 @hamburger-os @wdfk-prog

Changed Files (Click to expand)

• bsp/stm32/libraries/HAL_Drivers/drivers/drv_can.c
• bsp/stm32/libraries/HAL_Drivers/drivers/drv_gpio.h

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📊 Current Review Status (Last Updated: 2025-11-20 09:08 CST)

• ⌛ @Liang1795 Pending Review
• ⌛ @hamburger-os Pending Review
• ⌛ @wdfk-prog Pending Review

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📝 Review Instructions

1. 维护者可以通过单击此处来刷新审查状态: 🔄 刷新状态
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   Comment LGTM/lgtm after confirming approval

3. PR合并前需至少一位维护者确认
   PR must be confirmed by at least one maintainer before merging

ℹ️ 刷新CI状态操作需要具备仓库写入权限。
ℹ️ Refresh CI status operation requires repository Write permission.

[Copilot]

Pull Request Overview

This PR addresses two separate improvements to STM32 HAL drivers: (1) suppressing an unused variable compiler warning in the CAN driver's error path, and (2) adding comprehensive Doxygen documentation for the GET_PIN macro in the GPIO driver to improve code maintainability.

• Fixes unused variable warning in drv_can.c by marking mailbox_mask as intentionally unused
• Adds detailed Doxygen comments documenting the GET_PIN macro's functionality, parameters, usage examples, and platform-specific behavior

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
bsp/stm32/libraries/HAL_Drivers/drivers/drv_can.c	Suppresses unused variable warning for mailbox_mask in CAN send error path
bsp/stm32/libraries/HAL_Drivers/drivers/drv_gpio.h	Adds comprehensive Doxygen documentation block for GET_PIN macro