net/url: insufficient validation of bracketed IPv6 hostnames (CVE-2025-47912) [1.24 backport]

[gopherbot]

@neild requested issue #75678 to be considered for backport to the next 1.24 minor release.

@gopherbot please open backport issues for this security fix

[gopherbot]

Change https://go.dev/cl/709838 mentions this issue: [release-branch.go1.24] net/url: enforce stricter parsing of bracketed IPv6 hostnames

[gopherbot]

Closed by merging CL 709838 (commit d6d2f7b) to release-branch.go1.24.