PEP 673: Inline reference links.

This follows Guido's suggestion in python#2130.

pep-0673.rst

@@ -18,8 +18,8 @@ Abstract
 
 This PEP introduces a simple and intuitive way to annotate methods that return
 an instance of their class. This behaves the same as the ``TypeVar``-based
-approach specified in PEP 484 [#pep-484-self-type]_ but is more concise and
-easier to follow.
+approach specified in `PEP 484 <https://www.python.org/dev/peps/pep-0484>`_
+but is more concise and easier to follow.
 
 Motivation
 ==========
@@ -132,13 +132,15 @@ As in the above example, the type checker will correctly infer the type of
 Usage statistics
 ----------------
 
-We analyzed popular open-source projects [#self-type-usage-stats]_ and found
-that patterns like the above were used about **40%** as often as popular types
-like ``dict`` or ``Callable``. For example, in typeshed alone, such “Self”
-types are used 523 times, compared to 1286 uses of ``dict`` and 1314 uses of
-``Callable`` as of October 2021 [#callable-dict-usage-stats]_. This suggests
-that a ``Self`` type will be used quite often and users will benefit a lot
-from the simpler approach above.
+We `analyzed
+<https://github.com/pradeep90/annotation_collector/#self-type-stats>`_ popular
+open-source projects and found that patterns like the above were used about
+**40%** as often as popular types like ``dict`` or ``Callable``. For example,
+in typeshed alone, such “Self” types are used 523 times, compared to 1286 uses
+of ``dict`` and 1314 uses of ``Callable`` `as of October 2021
+<https://github.com/pradeep90/annotation_collector/#overall-stats-in-typeshed>`_.
+This suggests that a ``Self`` type will be used quite often and users will
+benefit a lot from the simpler approach above.
 
 Specification
 =============
@@ -495,8 +497,9 @@ is treated equivalently to:
             return self
 
 
-See [#protocol-self-type]_ for details on the behavior of TypeVars bound
-to protocols.
+See `PEP 544
+<https://www.python.org/dev/peps/pep-0544/#self-types-in-protocols>`_ for
+details on the behavior of TypeVars bound to protocols.
 
 Checking a class for compatibility with a protocol: If a protocol uses
 ``Self`` in methods or attribute annotations, then a class ``Foo`` is
@@ -753,85 +756,32 @@ Resources
 =========
 
 Similar discussions on a ``Self`` type in Python started in Mypy around 2016:
-[#mypy1212]_. However, the approach ultimately taken there was the bounded
-``TypeVar`` approach shown in our "before" examples. Other issues that discuss
-this include [#mypy2354]_.
+`Mypy issue #1212 <https://github.com/python/mypy/issues/1212>`_ - SelfType or
+another way to spell "type of self". However, the approach ultimately taken
+there was the bounded ``TypeVar`` approach shown in our "before" examples.
+Other issues that discuss this include `Mypy issue #2354
+<https://github.com/python/mypy/issues/2354>`_ - Self types in generic
+classes.
 
 **Pradeep** made a concrete proposal at the PyCon Typing Summit 2021:
- [#type-variables-for-all]_ (slides [#type-variables-for-all-slides]_).
+ `recorded talk <https://youtu.be/ld9rwCvGdhc?t=3260>`_, `slides
+ <https://drive.google.com/file/d/1x-qoDVY_OvLpIV1EwT7m3vm4HrgubHPG/view>`_.
 
 **James** brought up the proposal independently on typing-sig:
- [#james-typing-sig]_.
+`Typing-sig thread <https://mail.python.org/archives/list/typing-sig@python.org/thread/SJAANGA2CWZ6D6TJ7KOPG7PZQC56K73S/#B2CBLQDHXQ5HMFUMS4VNY2D4YDCFT64Q>`_.
 
 Other languages have similar ways to express the type of the enclosing class:
 
-+ TypeScript has the ``this`` type [#typescript-this-type]_
-+ Rust has the ``Self`` type [#rust-self-type]_
++ TypeScript has the ``this`` type (`TypeScript docs
+  <https://typescriptlang.org/docs/handbook/2/classes.html#this-types>`_)
++ Rust has the ``Self`` type (`Rust docs
+  <https://doc.rust-lang.org/std/keyword.SelfTy.html>`_)
 
 Thanks to the following people for their feedback on the PEP:
 
 Jia Chen, Rebecca Chen, Sergei Lebedev, Kaylynn Morgan, Tuomas Suutari, Alex
 Waygood, Shannon Zhu, and Никита Соболев
 
-References
-==========
-
-.. [#pep-484-self-type] PEP 484's approach to annotating ``self`` and ``cls``.
-
-    https://www.python.org/dev/peps/pep-0484/#annotating-instance-and-class-methods
-
-.. [#mypy1212] SelfType or another way to spell "type of self"
-
-    https://github.com/python/mypy/issues/1212
-
-.. [#mypy2354] Self types in generic classes
-
-    https://github.com/python/mypy/issues/2354
-
-.. [#type-variables-for-all] Type Variables for All talk
-
-    https://youtu.be/ld9rwCvGdhc?t=3260
-
-.. [#type-variables-for-all-slides] Slides
-
-    https://drive.google.com/file/d/1x-qoDVY_OvLpIV1EwT7m3vm4HrgubHPG/view
-
-.. [#james-typing-sig] Thread
-
-    https://mail.python.org/archives/list/typing-sig@python.org/thread/SJAANGA2CWZ6D6TJ7KOPG7PZQC56K73S/#B2CBLQDHXQ5HMFUMS4VNY2D4YDCFT64Q
-
-.. [#property-workaround] Property workaround
-
-    https://mypy-play.net/?mypy=latest&python=3.8&gist=ae886111451833e38737721a4153fd96
-
-.. [#self-type-usage-stats] Self type usage stats
-
-    https://github.com/pradeep90/annotation_collector/#self-type-stats
-
-.. [#callable-dict-usage-stats] ``Callable`` and ``dict`` usage stats
-
-    https://github.com/pradeep90/annotation_collector/#overall-stats-in-typeshed
-
-.. [#protocol-self-type] Protocol-bound ``TypeVar``
-
-    https://www.python.org/dev/peps/pep-0544/#self-types-in-protocols
-
-.. [#rust-self-type] Rust ``Self`` type
-
-    https://doc.rust-lang.org/std/keyword.SelfTy.html
-
-.. [#typescript-this-type] TypeScript ``this`` type
-
-    https://typescriptlang.org/docs/handbook/2/classes.html#this-types
-
-.. [#mypy-implementation] Mypy implementation
-
-    https://github.com/Gobot1234/mypy
-
-.. [#self-implementation] ``Self`` implementation
-
-    https://github.com/Gobot1234/typing/commit/8b41f2478144fcc32bac7a65afc3e490c24bb068
-
 Copyright
 =========