Lint RST on GitHub Actions and fix PEP 646 (#1802)

.github/workflows/lint.yml

@@ -0,0 +1,11 @@
+name: Lint
+
+on: [push, pull_request]
+
+jobs:
+  pre-commit:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+    - uses: pre-commit/action@v2.0.0

.pre-commit-config.yaml

@@ -0,0 +1,6 @@
+repos:
+  - repo: https://github.com/pre-commit/pygrep-hooks
+    rev: v1.7.1
+    hooks:
+      - id: rst-backticks
+      - id: rst-inline-touching-normal

Makefile

@@ -53,3 +53,7 @@ package: all rss
 	cp *.png build/peps/
 	cp *.rss build/peps/
 	tar -C build -czf build/peps.tar.gz peps
+
+lint:
+	pre-commit --version > /dev/null || python3 -m pip install pre-commit
+	pre-commit run --all-files

pep-0646.rst

@@ -281,7 +281,7 @@ As of this PEP, only a single type variable tuple may appear in a type parameter
 
     class Array(Generic[*Ts1, *Ts2]): ...  # Error
 
-(``Union`` is the one exception to this rule; see `Type Variable Tuples with ``Union```.)
+(``Union`` is the one exception to this rule; see `Type Variable Tuples with Union`_.)
 
 Type Prefixing
 --------------
@@ -360,7 +360,7 @@ parameterised with the same types.
     foo((0,), (1, 2))  # Error
     foo((0,), ('1',))  # Error
 
-Following `Type Variable Tuples Must Have Finite Length When Bound`, note
+Following `Type Variable Tuples Must Have Known Length`_, note
 that the following should *not* type-check as valid (even though it is, of
 course, valid at runtime):
 
@@ -401,9 +401,9 @@ Type variable tuples can also be used in the arguments section of a
 
 However, note that as of this PEP, if a type variable tuple does appear in
 the arguments section of a ``Callable``, it must appear alone.
-That is, `Type Prefixing` is not supported in the context of ``Callable``.
+That is, `Type Prefixing`_ is not supported in the context of ``Callable``.
 (Use cases where this might otherwise be desirable are likely covered through use
-of either a `ParamSpec` from PEP 612, or a type variable tuple in the `__call__`
+of either a ``ParamSpec`` from PEP 612, or a type variable tuple in the ``__call__``
 signature of a callback protocol from PEP 544.)
 
 Type Variable Tuples with ``Union``
@@ -473,7 +473,7 @@ Normal ``TypeVar`` instances can also be used in such aliases:
     # T is bound to `int`; Ts is bound to `bool, str`
     Foo[int, bool, str]
 
-Note that the same rules for `Type Prefixing` apply for aliases.
+Note that the same rules for `Type Prefixing`_ apply for aliases.
 In particular, only one ``TypeVarTuple`` may occur within an alias,
 and the ``TypeVarTuple`` must be at the end of the alias.