errors: introduce InputError and use it from commands and cmdutil This patch introduces a `InputError` class and replaces many uses of `error.Abort` by it in `commands` and `cmdutil`. This is a part of https://www.mercurial-scm.org/wiki/ErrorCategoriesPlan. There will later be a different class for state errors (to raise e.g. when there's an unfinished operation). It's not always clear when one should report an input error and when it should be a state error. We can always adjust later if I got something wrong in this patch (but feel free to point out any you notice now). Differential Revision: https://phab.mercurial-scm.org/D9167

--- a/tests/test-mq-qrefresh-interactive.t	Wed Oct 21 19:00:16 2020 -0700
+++ b/tests/test-mq-qrefresh-interactive.t	Tue Oct 06 22:36:15 2020 -0700
@@ -125,10 +125,10 @@
   $ hg commit -m aaa
   $ hg qrecord --config ui.interactive=false patch
   abort: running non-interactively, use qnew instead
-  [255]
+  [10]
   $ hg qnew -i --config ui.interactive=false patch
   abort: running non-interactively
-  [255]
+  [10]
   $ hg qnew -d '0 0' patch
 
 Changing files
@@ -179,7 +179,7 @@
 
   $ hg qrefresh -i --config ui.interactive=false
   abort: running non-interactively
-  [255]
+  [10]
   $ hg qrefresh -i -d '0 0' <<EOF
   > y
   > y