Fix typos

README_maintainer

@@ -61,7 +61,7 @@ marked on the patchwork server as "changes requested".
 
 : pw update -s "Changed Requested" -m "What to change" NNN
 
-This will sand an email to the contributor and the mailing list with a
+This will send an email to the contributor and the mailing list with a
 request for changes.  The =-m= message should not be more than one
 sentence and describe the requested changes.  If you need to explain
 in more detail, write a separate email to the contributor.
@@ -82,7 +82,7 @@ the HEAD state in the branch =t/patchNNN=.  To merge, do this:
 
 : pw merge -m "maintainer comment" NNN
 
-This will merge than patch into master, switch back to master and send
+This will merge the patch into master, switch back to master and send
 an email to both contributor and mailing list stating that this change
 has been accepted, along with the comment given in the =-m= message.
 
@@ -121,7 +121,7 @@ The release number for minor releases look like this:  =7.13.01=
 Minor releases are small amends to main releases.  Usually they fix
 bugs discovered in a main release.  Only the fix to the bug is
 bundled into a release, without the main development work going on in
-the master branch.  Since the big fix will also be needed in the
+the master branch.  Since the bug fix will also be needed in the
 master branch, usually the fix is made in master and then
 cherry-picked into maint.  When this is done, a release is made from
 maint with this command:
@@ -145,7 +145,7 @@ change only this file, use =--only=.
 
 This is still a significant headache.  Some hand work is needed here.
 
-Emacs uses bzr, and while I see all the advantages thiswould have, I
+Emacs uses bzr, and while I see all the advantages this would have, I
 cannot bring myself to switch away from git for my day-to-day work.
 So the way I have been doing things with Emacs is this: