Revert changes and use simpler approach

Author: AlenkaF

dev/tasks/docs/github.linux.yml

@@ -33,7 +33,6 @@ jobs:
         shell: bash
         env:
           ARROW_JAVA_SKIP_GIT_PLUGIN: true
-          DOCS_DEV: "1"
         run: |
           mkdir -p build
           archery docker run \

docs/source/conf.py

@@ -328,23 +328,15 @@
 # documentation.
 #
 
-# To enable the version switcher during a local build, set the
-# environment variable DOCS_DEV to "1".
-docs_dev = os.environ.get("DOCS_DEV", "0")
-print(f"DOCS_DEV : {docs_dev}")
-json_url = "/docs/_static/versions.json"
-
-if docs_dev == "1":
-    json_url = "https://arrow.apache.org/docs/_static/versions.json"
-    # json_url = "_static/versions.json"
-
 switcher_version = version
 if ".dev" in version:
     switcher_version = "dev/"
+    json_url = "https://arrow.apache.org/docs/_static/versions.json"
 else:
     # If we are not building dev version of the docs, we are building
     # docs for the stable version
     switcher_version = ""
+    json_url = "_static/versions.json"
 
 html_theme_options = {
     "show_toc_level": 2,

docs/source/developers/documentation.rst

@@ -92,12 +92,6 @@ These two steps are mandatory and must be executed in order.
    not sufficiently comprehensive. Portions of the Python API documentation
    will also not build without CUDA support having been built.
 
-.. note::
-
-   To enable the version switcher in a local documentation build, set the
-   environment variable ``DOCS_DEV=1`` before building, or run the build
-   command with it inline, for example: ``DOCS_DEV=1 make html``.
-
 After these steps are completed, the documentation is rendered in HTML
 format in ``arrow/docs/_build/html``.  In particular, you can point your browser
 at ``arrow/docs/_build/html/index.html`` to read the docs and review any changes