Update draft release notes to 2.2

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/RelNotes/2.2.0.txt

@@ -42,6 +42,15 @@ UI, Workflows & Features
    forgot to remove higher stage entries, or if it wanted to unresolve
    and forgot to remove the stage#0 entry).
 
+ * The temporary files "git mergetool" uses are named to avoid too
+   many dots in them (e.g. a temporary file for "hello.c" used to be
+   named e.g. "hello.BASE.4321.c" but now uses underscore instead,
+   e.g. "hello_BASE_4321.c").
+
+ * The temporary files "git mergetools" uses can be placed in a newly
+   creted temporary directory, instead of the current directory, by
+   setting the mergetool.writeToTemp configuration variable.
+
  * The "pre-receive" and "post-receive" hooks are no longer required
    to consume their input fully (not following this requirement used
    to result in intermittent errors in "git push").
@@ -68,10 +77,10 @@ UI, Workflows & Features
 
 Performance, Internal Implementation, etc.
 
- * The API to manipulate the "refs" is currently undergoing a revamp
+ * The API to manipulate the "refs" has been restructured to make it
-   to make it more transactional, with the eventual goal to allow
+   more transactional, with the eventual goal to allow all-or-none
-   all-or-none atomic updates and migrating the storage to something
+   atomic updates and migrating the storage to something other than
-   other than the traditional filesystem based one (e.g. databases).
+   the traditional filesystem based one (e.g. databases).
 
  * The lockfile API and its users have been cleaned up.
 
@@ -248,3 +257,7 @@ notes for details).
  * "gitweb" used deprecated CGI::startfrom, which was removed from
    CGI.pm as of 4.04; use CGI::start_from instead.
    (merge 4750f4b rm/gitweb-start-form later to maint).
+
+ * Newer versions of 'meld' breaks the auto-detection we use to see if
+   they are new enough to support the `--output` option.
+   (merge b12d045 da/mergetool-meld later to maint).