Repository: quantumlib/Cirq

Issue:
Remove build_doc CI job and dependencies
**Description of the issue**
Sphinx version update caused a [CI error](https://github.com/quantumlib/Cirq/actions/runs/7452039565/job/20274451752?pr=6399#step:5:15) with the `build_docs.sh` job. This job is no longer used since we instead use the quantumai website. Remove this job and it's dependencies (i.e Sphinx) 

**Cirq version**
1.4.0.dev20231221183905




Discussion:

Resolving patch:
diff --git a/dev_tools/incremental_coverage.py b/dev_tools/incremental_coverage.py
--- a/dev_tools/incremental_coverage.py
+++ b/dev_tools/incremental_coverage.py
@@ -21,7 +21,6 @@
 
 IGNORED_FILE_PATTERNS = [
     r'^dev_tools/.+',  # Environment-heavy code.
-    r'^rtd_docs/.+',  # Environment-heavy code.
     r'^.+_pb2(_grpc)?\.py$',  # Auto-generated protobuf code.
     r'^(.+/)?setup\.py$',  # Installation code.
     r'^(.+/)?_version\.py$',  # Installation code.
diff --git a/rtd_docs/__init__.py b/rtd_docs/__init__.py
deleted file mode 100644
--- a/rtd_docs/__init__.py
+++ /dev/null
@@ -1,13 +0,0 @@
-# Copyright 2018 The Cirq Developers
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     https://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
diff --git a/rtd_docs/conf.py b/rtd_docs/conf.py
deleted file mode 100644
--- a/rtd_docs/conf.py
+++ /dev/null
@@ -1,88 +0,0 @@
-# pragma: no cover
-
-# The content for all documentation lives in ../docs. That folder is
-# following the structure for the Google Quantum site configured for the
-# internal CMS, devsite. The readthedocs layer is a secondary, which generates
-# the content using sphinx to readthedocs.io until we go live with the devsite.
-#
-# This is the configuration file for the Sphinx documentation builder.
-# See http://www.sphinx-doc.org/en/master/config for help
-
-# -- Path setup --------------------------------------------------------------
-
-# If extensions (or modules to document with autodoc) are in another directory,
-# add these directories to sys.path here. If the directory is relative to the
-# documentation root, use os.path.abspath to make it absolute, like shown here.
-#
-
-import os
-import sys
-
-cirq_root_path = os.path.dirname(os.path.dirname(__file__))
-sys.path.insert(0, cirq_root_path)
-
-# -- Project information -----------------------------------------------------
-
-project = 'Cirq'
-copyright = '2018-2024, The Cirq Developers'  # pylint: disable=redefined-builtin
-author = 'The Cirq Developers'
-
-# The short X.Y version
-version = ""  # '.'.join(release.split('.')[:2])
-
-# -- General configuration ---------------------------------------------------
-
-# If your documentation needs a minimal Sphinx version, state it here.
-# needs_sphinx = '1.0'
-
-# Add any Sphinx extension module names here, as strings. They can be
-# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
-# ones.
-extensions = ['myst_parser', 'notfound.extension']
-
-# Add any paths that contain templates here, relative to this directory.
-templates_path = ['_templates']
-
-# Allow markdown includes.
-# http://www.sphinx-doc.org/en/main/markdown.html
-# The suffix(es) of source filenames.
-# You can specify multiple suffix as a list of string:
-#
-source_suffix = {'.rst': 'restructuredtext', '.md': 'markdown'}
-
-# The main toctree document.
-root_doc = 'index'
-
-# The language for content autogenerated by Sphinx. Refer to documentation
-# for a list of supported languages.
-#
-# This is also used if you do content translation via gettext catalogs.
-# Usually you set "language" from the command line for these cases.
-language = 'en'
-
-# List of patterns, relative to source directory, that match files and
-# directories to ignore when looking for source files.
-# This pattern also affects html_static_path and html_extra_path .
-exclude_patterns = ['Thumbs.db', '.DS_Store']
-
-# The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
-
-# -- Options for HTML output ---------------------------------------------
-
-html_theme = 'sphinx_rtd_theme'
-html_favicon = 'favicon.ico'
-# html_theme_options = {}
-
-# Custom sidebar templates, must be a dictionary that maps document names
-# to template names.
-#
-# The default sidebars (for documents that don't match any pattern) are
-# defined by theme itself.  Builtin themes are using these templates by
-# default: ``['localtoc.html', 'relations.html', 'sourcelink.html',
-# 'searchbox.html']``.
-#
-# html_sidebars = {}
-
-html_logo = 'Cirq_logo_notext.png'
-html_css_files = ['tweak-style.css']


Test patch: