purge: move extension into core mercurial The motivation is simple: it's nicer to avoid gating basic functionality. To reduce the risk of people shooting themselves in the feet, `--confirm` is now the default, unless the extensions is loaded.. For review of the body of the purge command, use this instead of what hg/phabricator will show (the block of code is modified, not just moved): Differential Revision: https://phab.mercurial-scm.org/D9820

--- a/relnotes/next	Mon Jan 18 10:24:11 2021 +0100
+++ b/relnotes/next	Mon Jan 18 10:24:20 2021 +0100
@@ -17,6 +17,8 @@
    can be e.g. `rebase`. As part of this effort, the default format
    from `hg rebase` was reorganized a bit.
 
+ * `hg purge` is now a core command using `--confirm` by default.
+
  * `hg strip`, from the strip extension, is now a core command, `hg
    debugstrip`. The extension remains for compatibility.