hgweb: add diffs to the json changeset template While it's possible to get the diff for each file individually via an obscure url that I'm not even sure is documented, (e.g. diff/{rev}/{filename}?style=json ), it is more convenient to provide the full diff from the changeset view. This is already normally computed for other non-JSON templates, so it seems like an oversight to omit it for the JSON one. The output format is a bit unwieldy but it's consistent with the existing format output by the aforementioned obscure url.

--- a/mercurial/templates/json/map	Fri Nov 15 15:56:25 2019 -0500
+++ b/mercurial/templates/json/map	Fri Nov 15 15:58:56 2019 -0500
@@ -66,6 +66,7 @@
   "user": {author|utf8|json},
   "parents": [{join(parent%changesetparent, ", ")}],
   "files": [{join(files, ", ")}],
+  "diff": [{join(diff, ", ")}],
   "phase": {phase|json}
   }'
 changesetbranch = '{name|utf8|json}'