ACP issue template: Fixed dead link

There was a link to a section about ACPs in the std-dev-guide. I rewrote the
issue template a bit as the exact section does not exist anymore. The issue
template now links to the chapter about the feature lifecycle instead (that
chapter also contains information about FCPs).

Also, fixed a minor grammatical error.

Author: EliasHolzmann

.github/ISSUE_TEMPLATE/api-change-proposal.md

@@ -38,9 +38,9 @@ Could this be written using existing APIs? If so, roughly what would that look l
 
 ## What happens now?
 
-This issue is part of the libs-api team [API change proposal process]. Once this issue is filed the libs-api team will review open proposals as capability becomes available. Current response times do not have a clear estimate, but may be up to several months.
+This issue contains an API change proposal (or ACP) and is part of the libs-api team [feature lifecycle]. Once this issue is filed, the libs-api team will review open proposals as capability becomes available. Current response times do not have a clear estimate, but may be up to several months.
 
-[API change proposal process]: https://std-dev-guide.rust-lang.org/feature-lifecycle/api-change-proposals.html
+[feature lifecycle]: https://std-dev-guide.rust-lang.org/development/feature-lifecycle.html
 
 ## Possible responses