Merge pull request #1003 from bmispelon/fix-tests-3be368c73e

Fix admin_views tests after commit 3be368c73e.
Added some further guidance to "accepted" triage stage

Now that DDN is gone, I felt it was worth some extra language
about what "accepted" means, and qualify what it means to be "safe"
to start writing a patch.
Made usage of assertTemplateUsed in admin_views tests

Thanks Baptiste Mispelon for the suggestion.
Fixed #20231 -- Don't use allow_lazy on smart_split
Fix #20223: Introduce keep_lazy as a replacement for allow_lazy.

The semantics stay the same but the new syntax allow the use of
keep_lazy as a decorator with the @-syntax.
It also makes sure that type parameters are passed to lazy,
which would result in an error otherwise.

The cleanups introduced in this change also incidentally fix #20222.
Fix #20221: make conditional_escape properly handle lazy strings.