discovery: replace "heads" by "changesets" in a output note (BC)

discovery: replace "heads" by "changesets" in a output note (BC)

When using `hg push --rev X`, the subset considered by discovery is only `::X`.
In addition, `X` can be any local revisions not just local heads. As a result
the message "all local heads known locally" can be misleading. We replace it
with the more accurate "all local changesets known remotely".

The message appears when in verbose not, so this is stricly speaking a BC
breakage. I am not sure this would be a real issue in practice...

--- a/mercurial/setdiscovery.py	Thu Sep 05 16:32:33 2019 -0700
+++ b/mercurial/setdiscovery.py	Sat Apr 27 02:04:05 2019 +0200
@@ -389,7 +389,7 @@
         return srvheadhashes, False, srvheadhashes
 
     if len(sample) == len(ownheads) and all(yesno):
-        ui.note(_("all local heads known remotely\n"))
+        ui.note(_("all local changesets known remotely\n"))
         ownheadhashes = [clnode(r) for r in ownheads]
         return ownheadhashes, True, srvheadhashes
 

--- a/tests/test-blackbox.t	Thu Sep 05 16:32:33 2019 -0700
+++ b/tests/test-blackbox.t	Sat Apr 27 02:04:05 2019 +0200
@@ -140,7 +140,7 @@
   comparing with $TESTTMP/blackboxtest
   query 1; heads
   searching for changes
-  all local heads known remotely
+  all local changesets known remotely
   changeset:   2:d02f48003e62c24e2659d97d30f2a83abe5d5d51
   tag:         tip
   phase:       draft

--- a/tests/test-largefiles.t	Thu Sep 05 16:32:33 2019 -0700
+++ b/tests/test-largefiles.t	Sat Apr 27 02:04:05 2019 +0200
@@ -1115,7 +1115,7 @@
   $ hg pull -v --lfrev 'heads(pulled())+min(pulled())'
   pulling from $TESTTMP/a
   searching for changes
-  all local heads known remotely
+  all local changesets known remotely
   6 changesets found
   uncompressed size of bundle content:
       1389 (changelog)

--- a/tests/test-narrow-widen-no-ellipsis.t	Thu Sep 05 16:32:33 2019 -0700
+++ b/tests/test-narrow-widen-no-ellipsis.t	Sat Apr 27 02:04:05 2019 +0200
@@ -116,7 +116,7 @@
   query 1; heads
   sending batch command
   searching for changes
-  all local heads known remotely
+  all local changesets known remotely
   sending narrow_widen command
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "changegroup" (params: * mandatory) supported (glob)

--- a/tests/test-setdiscovery.t	Thu Sep 05 16:32:33 2019 -0700
+++ b/tests/test-setdiscovery.t	Sat Apr 27 02:04:05 2019 +0200
@@ -64,7 +64,7 @@
   comparing with b
   query 1; heads
   searching for changes
-  all local heads known remotely
+  all local changesets known remotely
   elapsed time:  * seconds (glob)
   heads summary:
     total common heads:          2
@@ -86,7 +86,7 @@
   comparing with b
   query 1; heads
   searching for changes
-  all local heads known remotely
+  all local changesets known remotely
   elapsed time:  * seconds (glob)
   heads summary:
     total common heads:          1

--- a/tests/test-wireproto-exchangev2-shallow.t	Thu Sep 05 16:32:33 2019 -0700
+++ b/tests/test-wireproto-exchangev2-shallow.t	Sat Apr 27 02:04:05 2019 +0200
@@ -490,7 +490,7 @@
   received frame(size=2; request=3; stream=2; streamflags=encoded; type=command-response; flags=continuation)
   received frame(size=0; request=3; stream=2; streamflags=; type=command-response; flags=eos)
   searching for changes
-  all local heads known remotely
+  all local changesets known remotely
   sending 1 commands
   sending command changesetdata: {
     'fields': set([

--- a/tests/test-wireproto-exchangev2.t	Thu Sep 05 16:32:33 2019 -0700
+++ b/tests/test-wireproto-exchangev2.t	Sat Apr 27 02:04:05 2019 +0200
@@ -299,7 +299,7 @@
     ]
   }
   searching for changes
-  all local heads known remotely
+  all local changesets known remotely
   sending 1 commands
   sending command changesetdata: {
     'fields': set([