Add assignment form as etc/copyright-assign.txt

This change was discussed in:
https://lists.gnu.org/r/emacs-devel/2023-12/msg00326.html

* etc/copyright-assign.txt: New file copied from
https://www.gnu.org/s/gnulib/Copyright/request-assign.future
* doc/emacs/trouble.texi (Copyright Assignment):
* etc/TODO: Point to above new file.

doc/emacs/trouble.texi

@@ -1540,10 +1540,11 @@ to the FSF@.  For the reasons behind this, see
 @url{https://www.gnu.org/licenses/why-assign.html}.
 
 Copyright assignment is a simple process.  Residents of many countries
-can do it entirely electronically.  We can help you get started,
+can do it entirely electronically.  To get started, follow the
-including sending you the forms you should fill, and answer any
+instructions in the file @file{etc/copyright-assign.txt} in the Emacs
-questions you may have (or point you to the people with the answers),
+distribution.  We can answer any questions you may have (or point you to
-at the @email{emacs-devel@@gnu.org} mailing list.
+the people with the answers) at the @email{emacs-devel@@gnu.org} mailing
+list.
 
 (Please note: general discussion about why some GNU projects ask
 for a copyright assignment is off-topic for emacs-devel.

etc/TODO

@@ -11,12 +11,16 @@ it best.  Also to check that it hasn't been done already, since we
 don't always remember to update this file!  It is best to consult
 the latest version of this file in the Emacs source code repository.
 
-Since Emacs is an FSF-copyrighted package, please be prepared to sign
+Generally speaking, for non-trivial contributions to GNU Emacs and
-legal papers to transfer the copyright on your work to the FSF.
+packages stored in GNU ELPA, we require that the copyright be assigned
-Copyright assignment is a simple process.  Residents of some countries
+to the FSF.  For the reasons behind this, see:
-can do it entirely electronically.  We can help you get started, and
+https://www.gnu.org/licenses/why-assign.html
-answer any questions you may have (or point you to the people with the
+
-answers), at the emacs-devel@gnu.org mailing list.
+Copyright assignment is a simple process.  Residents of many countries
+can do it entirely electronically.  To get started, follow the
+instructions in the file etc/copyright-assign.txt in the Emacs
+distribution.  We can answer any questions you may have (or point you to
+the people with the answers) at the emacs-devel@gnu.org mailing list.
 
 For more information about getting involved, see the CONTRIBUTE file.
 

etc/copyright-assign.txt

@@ -0,0 +1,36 @@
+Please email the following information to assign@gnu.org, and we
+will send you the assignment form for your past and future changes.
+
+Please use your full legal name (in ASCII characters) as the subject
+line of the message.
+----------------------------------------------------------------------
+REQUEST: SEND FORM FOR PAST AND FUTURE CHANGES
+
+[What is the name of the program or package you're contributing to?]
+Emacs
+
+[Did you copy any files or text written by someone else in these changes?
+Even if that material is free software, we need to know about it.]
+
+
+[Do you have an employer who might have a basis to claim to own
+your changes?  Do you attend a school which might make such a claim?]
+
+
+[For the copyright registration, what country are you a citizen of?]
+
+
+[What year were you born?]
+
+
+[Please write your email address here.]
+
+
+[Please write your postal address here.]
+
+
+
+
+
+[Which files have you changed so far, and which new files have you written
+so far?]