Remove outdated "single sourcing package version" advice

source/guides/section-build-and-publish.rst

@@ -7,7 +7,6 @@ Building and Publishing
 
    writing-pyproject-toml
    distributing-packages-using-setuptools
-   single-sourcing-package-version
    dropping-older-python-versions
    packaging-binary-extensions
    packaging-namespace-packages

source/guides/writing-pyproject-toml.rst

@@ -110,8 +110,8 @@ similar. In such cases, you should mark the field as dynamic using, e.g.,
 
 
 When a field is dynamic, it is the build backend's responsibility to
-fill it.  Consult your build backend's documentation to learn how it
-does it.
+fill it.  Consult :ref:`Single sourcing the version discussion` for more
+details.
 
 
 Basic information
@@ -163,8 +163,7 @@ This field is required, although it is often marked as dynamic using
    dynamic = ["version"]
 
 This allows use cases such as filling the version from a ``__version__``
-attribute or a Git tag. Consult :ref:`Single sourcing the version` for more
-details.
+attribute or a Git tag.
 
 
 Dependencies and requirements