[MRG+1] Fix typos in documentation (#9878)

* Fix grammatical error in

* Correct capitalization of "GitHub"

Used command `find . -type f -exec sed -i 's/Github/GitHub/g' {} \;` (h/t: https://stackoverflow.com/a/15402972)

# Conflicts:
#	doc/developers/contributing.rst

CONTRIBUTING.md

@@ -170,7 +170,7 @@ list or on the GitHub issue).
 
 Filing bugs
 -----------
-We use Github issues to track all bugs and feature requests; feel free to
+We use GitHub issues to track all bugs and feature requests; feel free to
 open an issue if you have found a bug or wish to see a feature implemented.
 
 It is recommended to check that your issue complies with the

doc/faq.rst

@@ -55,7 +55,7 @@ please make sure to include the full traceback that you obtain when running the
 reproduction script.
 
 For bug reports or feature requests, please make use of the
-`issue tracker on Github <https://github.com/scikit-learn/scikit-learn/issues>`_.
+`issue tracker on GitHub <https://github.com/scikit-learn/scikit-learn/issues>`_.
 
 There is also a `scikit-learn Gitter channel
 <https://gitter.im/scikit-learn/scikit-learn>`_ where some users and developers

doc/sphinxext/sphinx_issues.py

@@ -33,7 +33,7 @@
 def user_role(name, rawtext, text, lineno,
               inliner, options=None, content=None):
     """Sphinx role for linking to a user profile. Defaults to linking to
-    Github profiles, but the profile URIS can be configured via the
+    GitHub profiles, but the profile URIS can be configured via the
     ``issues_user_uri`` config value.
 
     Example: ::
@@ -104,7 +104,7 @@ def setup(app):
     # Format template for issues URI
     # e.g. 'https://github.com/sloria/marshmallow/issues/{issue}
     app.add_config_value('issues_uri', default=None, rebuild='html')
-    # Shortcut for Github, e.g. 'sloria/marshmallow'
+    # Shortcut for GitHub, e.g. 'sloria/marshmallow'
     app.add_config_value('issues_github_path', default=None, rebuild='html')
     # Format template for user profile URI
     # e.g. 'https://github.com/{user}'

doc/themes/scikit-learn/layout.html

@@ -203,7 +203,7 @@ <h2>Machine Learning in Python</h2>
 {% endblock %}
 
 {% block content %}
-<!-- Github "fork me" ribbon -->
+<!-- GitHub "fork me" ribbon -->
 <a href="https://github.com/scikit-learn/scikit-learn">
   <img class="fork-me"
        style="position: absolute; top: 0; right: 0; border: 0;"

sklearn/linear_model/tests/test_bayes.py

@@ -36,7 +36,7 @@ def test_bayesian_on_diabetes():
 
 
 def test_bayesian_ridge_parameter():
-    # Test correctness of lambda_ and alpha_ parameters (Github issue #8224)
+    # Test correctness of lambda_ and alpha_ parameters (GitHub issue #8224)
     X = np.array([[1, 1], [3, 4], [5, 7], [4, 1], [2, 6], [3, 10], [3, 2]])
     y = np.array([1, 2, 3, 2, 0, 4, 5]).T