Check links in CI.

docs/source/conf.py

@@ -232,6 +232,10 @@ intersphinx_mapping = {'https://docs.python.org/': None}
 # https://github.com/rtfd/recommonmark/blob/master/docs/conf.py#L296
 github_doc_root = 'https://github.com/jupyterlab/jupyterlab/tree/master/docs/'
 
+# We can't rely on anchors because GitHub dynamically renders them for
+# markdown documents.
+linkcheck_anchors = False
+
 def setup(app):
     app.add_config_value('recommonmark_config', {
         'url_resolver': lambda url: github_doc_root + url,

scripts/travis_script.sh

@@ -41,7 +41,8 @@ if [[ $GROUP == docs ]]; then
 
     # Verify tutorial docs build
     pushd docs
-    pip install "sphinx<1.8" sphinx_rtd_theme recommonmark
+    pip install sphinx sphinx_rtd_theme recommonmark
+    make linkcheck
     make html
     popd
 fi