Go's semantic import versioning requires v2+ modules to include the
major version in the module path. This enables using proper version
tags (v3.x.x) instead of pseudo-versions.
Updated module path: code.gitcaddy.com/server/v3
Clarify when "string" should be used (and be escaped), and when
"template.HTML" should be used (no need to escape)
And help PRs like #29059 , to render the error messages correctly.
