fix documentation bugs

doc/example/package.rst

@@ -20,7 +20,7 @@ setuptools
 Using the ``pyproject.toml`` file at the root folder (alongside ``setup.py``) one can specify
 build requirements.
 
-.. code-block:: python
+.. code-block:: ini
 
     [build-system]
     requires = [
@@ -29,14 +29,19 @@ build requirements.
     ]
     build-backend = "setuptools.build_meta"
 
+.. code-block:: ini
+
+   # tox.ini
+   [tox]
+   build_isolated = True
 
 flit
 ----
 `flit <https://flit.readthedocs.io/en/latest/>`_ requires ``Python 3``, however the generated source
 distribution can be installed under ``python 2``. Furthermore it does not require a ``setup.py``
 file as that information is also added to the ``pyproject.toml`` file.
 
-.. code-block:: python
+.. code-block:: ini
 
     [build-system]
     requires = ["flit >= 1.1"]
@@ -47,3 +52,9 @@ file as that information is also added to the ``pyproject.toml`` file.
     author = "Happy Harry"
     author-email = "happy@harry.com"
     home-page = "https://github.com/happy-harry/is"
+
+.. code-block:: ini
+
+   # tox.ini
+   [tox]
+   build_isolated = True

src/tox/config.py

@@ -1006,9 +1006,7 @@ def __init__(self, config, inipath):  # noqa
 
         config.skipsdist = reader.getbool("skipsdist", all_develop)
         config.isolated_build = reader.getbool("isolated_build", False)
-        config.isolated_build_env = reader.getstring(
-            "isolated_build_env", ".package"
-        )
+        config.isolated_build_env = reader.getstring("isolated_build_env", ".package")
         if config.isolated_build is True:
             name = config.isolated_build_env
             if name not in config.envconfigs:

tox.ini

@@ -28,7 +28,7 @@ basepython = python3.7
 extras = docs
 changedir = {toxinidir}
 commands = sphinx-build -d "{toxworkdir}/docs_doctree" doc "{toxworkdir}/docs_out" --color -W -bhtml {posargs}
-           python -c 'print("documentation available under file://{toxworkdir}/docs_out/index.html")'
+           python -c 'import pathlib; print("documentation available under file://\{0\}".format(pathlib.Path(r"{toxworkdir}") / "docs_out" / "index.html"))'
 
 [testenv:package-description]
 description = check that the long description is valid
@@ -52,7 +52,7 @@ deps = pre-commit == 1.10.3
 skip_install = True
 changedir = {toxinidir}
 commands = pre-commit run --all-files --show-diff-on-failure
-           python -c 'print("hint: run {envdir}/bin/pre-commit install to add checks as pre-commit hook")'
+           python -c 'import pathlib; print("hint: run \{\} install to add checks as pre-commit hook".format(pathlib.Path(r"{envdir}") / "bin" / "pre-commit"))'
 
 
 [testenv:coverage]