Fix documentation of 'ses-define-local-printer'

* doc/misc/ses.texi (Printer functions): Fix whitespace between
sentences and punctuation.  Add an index entry for
'ses-define-local-printer'.

doc/misc/ses.texi

@@ -377,6 +377,7 @@ Undo previous action (@code{(undo)}).
 @findex ses-read-cell-printer
 @findex ses-read-column-printer
 @findex ses-read-default-printer
+@findex ses-define-local-printer
 @findex ses-center
 @findex ses-center-span
 @findex ses-dashfill
@@ -435,13 +436,13 @@ Centering with dashes and spill-over.
 Centering with tildes (~) and spill-over.
 @end table
 
-You can define printer function local to a sheet with command
-@code{ses-define-local-printer}. For instance define printer
-@samp{foo} to @code{"%.2f"} and then use symbol @samp{foo} as a
-printer function. Then, if you call again
+You can define printer function local to a sheet with the command
+@code{ses-define-local-printer}.  For instance, define a printer
+@samp{foo} to @code{"%.2f"}, and then use symbol @samp{foo} as a
+printer function.  Then, if you call again
 @code{ses-define-local-printer} on @samp{foo} to redefine it as
-@code{"%.3f"} all the cells using printer @samp{foo} will be reprinted
-accordingly.
+@code{"%.3f"}, all the cells using printer @samp{foo} will be
+reprinted accordingly.
 
 @node Clearing cells
 @section Clearing cells

etc/NEWS

@@ -739,6 +739,7 @@ plain text parts, if display of HTML email is possible; customize the
 *** In the commands that make summaries by subject, recipients, or senders,
 you can no longer use commas to separate regular expressions.
 
++++
 ** SES now supports local printer functions; see `ses-define-local-printer'.
 
 ** sh-script