doc: git-push: clarify intro

From user feedback, 5 users are unsure what "ref" and/or "objects" means
in this context. 3 users said they don't know what "complete the refs"
means.

Many users also commented that receive hooks do not seem like the most
important thing to know about `git push`, and that this information
should not be the second sentence in the man page.

Use more familiar language to make it more accessible to users who do
not know what a "ref" is and move the "hooks" comment to the end.

Signed-off-by: Julia Evans <julia@jvns.ca>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-push.adoc

@@ -19,12 +19,9 @@ SYNOPSIS
 DESCRIPTION
 -----------
 
-Updates remote refs using local refs, while sending objects
+Updates one or more branches, tags, or other references in a remote
-necessary to complete the given refs.
+repository from your local repository, and sends all necessary data
-
+that isn't already on the remote.
-You can make interesting things happen to a repository
-every time you push into it, by setting up 'hooks' there.  See
-documentation for linkgit:git-receive-pack[1].
 
 When the command line does not specify where to push with the
 `<repository>` argument, `branch.*.remote` configuration for the
@@ -44,6 +41,10 @@ corresponding upstream branch, but as a safety measure, the push is
 aborted if the upstream branch does not have the same name as the
 local one.
 
+You can make interesting things happen to a repository
+every time you push into it, by setting up 'hooks' there.  See
+documentation for linkgit:git-receive-pack[1].
+
 
 OPTIONS[[OPTIONS]]
 ------------------