ci: remove doc generation

This has apparently been broken for a while, and with docs.rs, we don't
need it any more.

Tangentially, this method seemingly required a personal access token, which
seems like a bad idea in a shared repo.

Author: BurntSushi

.travis.yml

@@ -20,9 +20,6 @@ addons:
     - python
     - python-virtualenv
 after_success: ci/after_success.sh
-env:
-  global:
-    secure: "GdGE0kFYiJGccVZligur7JlWRCy49eH6uWPl71mrnaaW8jLHmkva0jVb0LB9e5ol3YMaMCgrwM2pcj3Uk2C08YcGIoEKOLlDVho351KaD6XfclZ29CQTAPMz4Xut2IcB4YeuZlDrOnM26guTIOtn2NAjeQgOhpM/ErzVBgkB+wQ="
 notifications:
   email:
     on_success: never

ci/after_success.sh

@@ -12,15 +12,6 @@ fi
 export RUSTFLAGS="-C target-feature=+ssse3"
 env
 
-# Build and upload docs.
-echo '<meta http-equiv=refresh content=0;url=regex/index.html>' > target/doc/index.html
-ve=$(mktemp -d)
-virtualenv "$ve"
-"$ve"/bin/pip install --upgrade pip
-"$ve"/bin/pip install ghp-import
-"$ve"/bin/ghp-import -n target/doc
-git push -qf https://${TOKEN}@github.com/${TRAVIS_REPO_SLUG}.git gh-pages
-
 # Install kcov.
 tmp=$(mktemp -d)
 pushd "$tmp"