Revert "Merge pull #793: Dev Docs: New Glossary & JS Search Box"

This reverts commit e3dcf0ce1f, reversing
changes made to c71e9fdf2d.

Once again we had a broken new plugin that Travis CI and local building
didn't catch.

_data/glossary/en/regression-test-mode.yaml

@@ -1,31 +0,0 @@
----
-# This file is licensed under the MIT License (MIT) available on
-# http://opensource.org/licenses/MIT.
-
-required:
-                                           #-------------40 characters-------------#
-    title_max_40_characters_no_formatting: Regtest, Regression Test Mode
-
-    summary_max_255_characters_no_formatting: >
-        A local testing environment in which developers can almost
-        instantly generate blocks on demand for testing events, and can
-        create private satoshis with no real-world value.
-
-    synonyms_shown_in_glossary_capitalize_first_letter:
-        - Regtest
-        - Regression test mode
-
-optional:
-    synonyms_and_pluralizations_not_shown_in_glossary:
-        - regtests
-        - regression test modes
-        - regtest mode
-        - regtest modes
-
-    not_to_be_confused_with_capitalize_first_letter:
-        - Testnet (a global testing environment which mostly mimics mainnet)
-
-    links_html_or_markdown_style_capitalize_first_letter:
-        - "[Regtest mode](/en/developer-examples#regtest-mode) --- Bitcoin.org Developer Examples"
-
----