Improve language on CONTRIBUTING file

As @marwahaha said

> "master repository" feels overloaded,
> since typically "master" refers to a branch name.

We are going to use "originating repository".

diff --git a/bin/lesson_initialize.py b/bin/lesson_initialize.py
index cf9735ec29bdd07bebfcdaffa3de5ee43d44325f..aeffdec7ac5d9be576ca94434c677f51c6a8db55 100755 (executable)
--- a/bin/lesson_initialize.py
+++ b/bin/lesson_initialize.py
@@ -126,22 +126,22 @@ Each lesson has two maintainers who review issues and pull requests or encourage
 The maintainers are community volunteers and have final say over what gets merged into the lesson.
 To use the web interface for contributing to a lesson:
 
-1.  Fork the master repository to your GitHub profile.
+1.  Fork the originating repository to your GitHub profile.
 2.  Within your version of the forked repository, move to the `gh-pages` branch and
 create a new branch for each significant change being made.
 3.  Navigate to the file(s) you wish to change within the new branches and make revisions as required.
 4.  Commit all changed files within the appropriate branches.
 5.  Create individual pull requests from each of your changed branches
-to the `gh-pages` branch within the master repository.
+to the `gh-pages` branch within the originating repository.
 6.  If you receive feedback, make changes using your issue-specific branches of the forked
 repository and the pull requests will update automatically.
 7.  Repeat as needed until all feedback has been addressed.
 
-When starting work, please make sure your clone of the master `gh-pages` branch is up-to-date
+When starting work, please make sure your clone of the originating `gh-pages` branch is up-to-date
 before creating your own revision-specific branch(es) from there.
 Additionally, please only work from your newly-created branch(es) and *not*
-your clone of the master `gh-pages` branch.
-Lastly, published copies of all the lessons are available in the `gh-pages` branch of the master
+your clone of the originating `gh-pages` branch.
+Lastly, published copies of all the lessons are available in the `gh-pages` branch of the originating
 repository for reference while revising.
 
 ## Other Resources