fix: ipv6 not effective for redir/tproxy

[spongebob888]

🤔 This is a ...

• New feature
• Bug fix
• Performance optimization
• Enhancement feature
• Refactoring
• Code style optimization
• Test Case
• Branch merge
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🔗 Related issue link

💡 Background and solution

IPV6 switch is not effective is bindaddress is not explicitly set to "::"

This PR sets the bindaddress to "::" if it is not explicitly set and ipv6 option is on

📝 Changelog

☑️ Self-Check before Merge

⚠️ Please check all items below before requesting a reviewing. ⚠️

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[codecov]

Codecov Report

Attention: Patch coverage is 77.77778% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
clash-lib/src/config/internal/convert/general.rs	75.00%	1 Missing ⚠️
clash-lib/src/config/internal/convert/listener.rs	66.66%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

[ibigbug]

if you change the default value here to unspecified and match it with the ipv6 switch in the listener, would it work? https://github.com/watfaq/clash-rs/blob/master/clash-lib/src/config/internal/config.rs#L126

[spongebob888]

Then. If user set explicitly bind-address:0.0.0.0 and ipv6: true will change bind-address:[::] which may be confusing

[spongebob888]

We can't distinguish between user set bind-address to 0.0.0.0 or empty field

[ibigbug]

Which should be fine? It they want 0.0.0.0 and ipv6 it would work too if you listen ::? If it's dual stack.

I just think making it optional adds extra complexity to match it instead of simply unwrap it

[spongebob888]

OK