Overlong translation files may cause repo to become "dirty"

Problem:  Overlong translation files may cause repo to become "dirty"
Solution: Add a test into check.vim to warn for lines being longer than
          80 virt columns

related: #14490

Signed-off-by: Christian Brabandt <cb@256bit.org>

src/po/check.vim

@@ -226,6 +226,14 @@ elseif ctu
   " endif
 endif
 
+" Check that all lines are no longer than 80 chars
+let overlong = search('\%>80v', 'n')
+if overlong > 0
+  echomsg "Lines should be wrapped at 80 columns"
+  if error == 0
+    let error = overlong
+  endif
+endif
 
 if error == 0
   " If all was OK restore the view.