docs: Add details for automatic syncing of debug.yaml

[Revolyssup]

Description

Fixes #9598

Checklist

• I have explained the need for this PR and the problem it solves
• I have explained the changes or the new features added to this PR
• I have added tests corresponding to this change
• I have updated the documentation to reflect this change
• I have verified that this change is backward compatible (If not, please discuss on the APISIX mailing list first)

[Revolyssup]

@kayx23 Please review

[kayx23]

Suggested change

	APISIX syncs the configuration passed in debug.yaml on startup and then checks if the file was modified on an interval of 1 second. If the file is changed, then it resyncs the debug configuration so that users don't have to reload for the debug configuration to take effect.
	APISIX loads the configurations of `debug.yaml` on startup and then checks if the file is modified on an interval of 1 second. If the file is changed, APISIX automatically applies the configuration changes.

[kayx23]

@Revolyssup could you help confirm in code if:

• 1 second is the default
• 1 second could be modified by config under /conf (or is it hardcoded)

[Revolyssup]

@kayx23 Here you can see its hardcoded

apisix/apisix/debug.lua

Line 311 in 01c583d

ngx.timer.every(1, sync_debug_status)

[Revolyssup]

@kayx23 Committed your suggestions.

[kayx23]

@kayx23 Committed your suggestions.

there's a comment too, please check

[Revolyssup]

@kayx23 Committed your suggestions.

there's a comment too, please check

@kayx23 replied.