"Improve page" links for examples and tutorials

Adds the sphinx-gallery configuration to the template so we can link to
the Github edit page for the gallery .py files.
The template also identifies the index.html files and directs them to
the README.txt files.

Author: leouieda

docs/_templates/breadcrumbs.html

@@ -6,11 +6,21 @@
 {% block breadcrumbs_aside %}
     <li class="source-link">
         {% if hasdoc(pagename) %}
-            {% if pagename.startswith("api/") or pagename.startswith("tutorials/") or pagename.startswith("examples/")%}
+            {% if pagename.startswith(api_dir) %}
                 {% set title = "Suggested improvement for " + pagename %}
                 {% set body = "Please describe what could be improved about this page or the typo/mistake that you found:" %}
                 <a href="https://github.com/{{ github_repo }}/issues/new?title={{ title|urlencode }}&body={{ body|urlencode }}"
                    class="fa fa-github"> Improve this page</a>
+            {% elif pagename.split("/")[0] in galleries %}
+                {% set gallery_path = gallery_dir[pagename.split("/")[0]] %}
+                {% set example_script = pagename|replace(pagename.split("/")[0], gallery_dir[pagename.split("/")[0]]) %}
+                {% if pagename.split("/")[-1] == "index" %}
+                    {% set example_script = example_script|replace("index", "README.txt") %}
+                {% else %}
+                    {% set example_script = example_script + ".py" %}
+                {% endif %}
+                <a href="https://github.com/{{ github_repo }}/edit/{{ github_version }}/{{ doc_path }}/{{ example_script }}"
+                   class="fa fa-github"> Improve this page</a>
             {% else %}
                 <a href="https://github.com/{{ github_repo }}/edit/{{ github_version }}/{{ doc_path }}/{{ pagename }}{{ suffix }}"
                    class="fa fa-github"> Improve this page</a>

docs/conf.py

@@ -175,6 +175,10 @@ def setup(app):
 # links to the Github repository sources and issues
 html_context = {
     'doc_path': 'docs',
+    'galleries': sphinx_gallery_conf['gallery_dirs'],
+    'gallery_dir': dict(zip(sphinx_gallery_conf['gallery_dirs'],
+                            sphinx_gallery_conf['examples_dirs'])),
+    'api_dir': 'api/generated',
     'github_repo': 'Unidata/MetPy',
     'github_version': 'master',  # Make changes to the master branch
 }