Link to pyproject.toml guide in "Packaging Python projects" tutorial

Replace links to the "Declaring project metadata" specification with
links to the "Writing pyproject.toml guide" since this is more likely
what the user wants after a tutorial. Also harmonize with the guide
slightly and leave link to version specifier specification (advanced
reading) for the guide.

Author: jeanas

source/guides/writing-pyproject-toml.rst

@@ -28,8 +28,8 @@ Most of the time, you will directly write the value of a field in
 
 However, in some cases, it is useful to let your build backend compute
 the metadata for you. For example: many build backends can read the
-version from a ``__version__`` attribute in your code, or similar.
-In such cases, you should mark the field as dynamic using, e.g.,
+version from a ``__version__`` attribute in your code, a Git tag, or
+similar. In such cases, you should mark the field as dynamic using, e.g.,
 
 .. code-block:: toml
 

source/tutorials/packaging-projects.rst

@@ -214,17 +214,16 @@ following this tutorial.
     ]
 
     [project.urls]
-    "Homepage" = "https://github.com/pypa/sampleproject"
-    "Bug Tracker" = "https://github.com/pypa/sampleproject/issues"
+    Homepage = "https://github.com/pypa/sampleproject"
+    Issues = "https://github.com/pypa/sampleproject/issues"
 
 - ``name`` is the *distribution name* of your package. This can be any name as
   long as it only contains letters, numbers, ``.``, ``_`` , and ``-``. It also
   must not already be taken on PyPI. **Be sure to update this with your
   username** for this tutorial, as this ensures you won't try to upload a
   package with the same name as one which already exists.
-- ``version`` is the package version. See the :ref:`version specifier specification <version-specifiers>`
-  for more details on versions. Some build backends allow it to be specified
-  another way, such as from a file or a git tag.
+- ``version`` is the package version. (Some build backends allow it to be
+  specified another way, such as from a file or Git tag.)
 - ``authors`` is used to identify the author of the package; you specify a name
   and an email for each author. You can also list ``maintainers`` in the same
   format.
@@ -233,9 +232,9 @@ following this tutorial.
   package. This is shown on the package detail page on PyPI.
   In this case, the description is loaded from :file:`README.md` (which is a
   common pattern). There also is a more advanced table form described in the
-  :ref:`project metadata specification <declaring-project-metadata>`.
+  :ref:`pyproject.toml guide <writing-pyproject-toml>`.
 - ``requires-python`` gives the versions of Python supported by your
-  project. Installers like :ref:`pip` will look back through older versions of
+  project. An installer like :ref:`pip` will look back through older versions of
   packages until it finds one that has a matching Python version.
 - ``classifiers`` gives the index and :ref:`pip` some additional metadata
   about your package. In this case, the package is only compatible with Python
@@ -247,10 +246,11 @@ following this tutorial.
 - ``urls`` lets you list any number of extra links to show on PyPI.
   Generally this could be to the source, documentation, issue trackers, etc.
 
-See the :ref:`project metadata specification <declaring-project-metadata>` for
-details on these and other fields that can be defined in the ``[project]``
-table. Other common fields are ``keywords`` to improve discoverability and the
-``dependencies`` that are required to install your package.
+See the :ref:`pyproject.toml guide <writing-pyproject-toml>` for details
+on these and other fields that can be defined in the ``[project]``
+table. Other common fields are ``keywords`` to improve discoverability
+and the ``dependencies`` that are required to install your package.
+
 
 Creating README.md
 ------------------