docs: fix language regarding master

docs/conf.py

@@ -16,8 +16,8 @@ extensions = ['sphinx.ext.mathjax',
               'sphinx.ext.intersphinx',
               'sphinx_copybutton']
 
-# The master toctree document.
-master_doc = 'index'
+# The root toctree document.
+root_doc = master_doc = "index"
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.

docs/contributing/index.rst

@@ -9,7 +9,7 @@ Your contribution is integral to the future of the project. Thank you!
 
 This section contains documentation for people who want to contribute.
 
-You can find the `source code on GitHub <https://github.com/jupyterhub/the-littlest-jupyterhub/tree/master/tljh>`_
+You can find the `source code on GitHub <https://github.com/jupyterhub/the-littlest-jupyterhub/tree/HEAD/tljh>`_
 
 .. toctree::
    :titlesonly:

docs/howto/admin/systemd.rst

@@ -7,8 +7,8 @@ Customizing ``systemd`` services
 By default, TLJH configures two ``systemd`` services to run JupyterHub and Traefik.
 
 These services come with a default set of settings, which are specified in
-`jupyterhub.service <https://github.com/jupyterhub/the-littlest-jupyterhub/blob/master/tljh/systemd-units/jupyterhub.service>`_ and
-`traefik.service <https://github.com/jupyterhub/the-littlest-jupyterhub/blob/master/tljh/systemd-units/traefik.service>`_.
+`jupyterhub.service <https://github.com/jupyterhub/the-littlest-jupyterhub/blob/HEAD/tljh/systemd-units/jupyterhub.service>`_ and
+`traefik.service <https://github.com/jupyterhub/the-littlest-jupyterhub/blob/HEAD/tljh/systemd-units/traefik.service>`_.
 They look like the following:
 
 .. code-block:: bash

docs/howto/content/nbgitpuller.rst

@@ -41,7 +41,7 @@ Step 1: Generate nbgitpuller link
 **Generate the link with a Binder app**.
 
 #. The easiest way to generate an nbgitpuller link is to use the
-   `mybinder.org based application <https://mybinder.org/v2/gh/jupyterhub/nbgitpuller/master?urlpath=apps/binder%2Flink_generator.ipynb>`_.
+   `mybinder.org based application <https://mybinder.org/v2/gh/jupyterhub/nbgitpuller/HEAD?urlpath=apps/binder%2Flink_generator.ipynb>`_.
    Open it, and wait for it to load.
 
    .. image:: ../../images/nbgitpuller/binder-progress.png

docs/topic/customizing-installer.rst

@@ -97,7 +97,7 @@ in your new hub, you would run:
 
     curl -L https://tljh.jupyter.org/bootstrap.py \
      | sudo python3 - \
-       --user-requirements-txt-url https://raw.githubusercontent.com/data-8/materials-sp18/master/requirements.txt
+       --user-requirements-txt-url https://raw.githubusercontent.com/data-8/materials-sp18/HEAD/requirements.txt
 
 The URL **must** point to a working requirements.txt. If there are any errors, the installation
 will fail.