Improved refcount debugging by printing function and line information while *destroy as well

[pranavrth]

No description provided.

[Copilot]

Pull request overview

This PR enhances refcount debugging capabilities by adding function and line information tracking for rd_refcnt_sub operations, matching the existing functionality for rd_refcnt_add.

Key Changes:

• Introduced rd_refcnt_sub_fl() macro to accept function and line parameters
• Updated rd_refcnt_sub() to use __FUNCTION__ and __LINE__ macros via the new _fl variant
• Added no-op rd_refcnt_sub_fl() definition for non-debug builds

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