PR: Transform static typing md to rst (#381)

* Transform static typing md to rst

* fix warning

Author: steff456

spec/design_topics/static_typing.md renamed to spec/design_topics/static_typing.rst

@@ -1,43 +1,45 @@
-# Static typing
+Static typing
+=============
 
 Good support for static typing both in array libraries and array-consuming
 code is desirable. Therefore the exact type or set of types for each
 parameter, keyword and return value is specified for functions and methods -
-see {ref}`function-and-method-signatures`. That section specifies arrays
-simply as `array`; what that means is dealt with in this section.
+see :ref:`function-and-method-signatures`. That section specifies arrays
+simply as ``array``; what that means is dealt with in this section.
 
 Introducing type annotations in libraries became more relevant only when
 Python 2.7 support was dropped at the start of 2020. As a consequence, using
 type annotations with array libraries is largely still a work in progress.
-This version of the API standard does not deal with trying to type _array
-properties_ like shape, dimensionality or dtype, because that's not a solved
+This version of the API standard does not deal with trying to type *array
+properties* like shape, dimensionality or dtype, because that's not a solved
 problem in individual array libraries yet.
 
-An `array` type annotation can mean either the type of one specific array
+An ``array`` type annotation can mean either the type of one specific array
 object, or some superclass or typing Protocol - as long as it is consistent
-with the array object specified in {ref}`array-object`. To illustrate by
+with the array object specified in :ref:`array-object`. To illustrate by
 example:
 
-```python
-# `Array` is a particular class in the library
-def sin(x: Array, / ...) -> Array:
-    ...
-```
-
-and 
-
-```python
-# There's some base class `_BaseArray`, and there may be multiple
-# array subclasses inside the library
-A = TypeVar('A', bound=_BaseArray)
-def sin(x: A, / ...) -> A:
-    ...
-```
+.. code-block:: python
+
+   # `Array` is a particular class in the library
+   def sin(x: Array, / ...) -> Array:
+       ...
+
+and
+
+.. code-block:: python
+
+   # There's some base class `_BaseArray`, and there may be multiple
+   # array subclasses inside the library
+   A = TypeVar('A', bound=_BaseArray)
+   def sin(x: A, / ...) -> A:
+       ...
+
 should both be fine. There may be other variations possible. Also note that
 this standard does not require that input and output array types are the same
 (they're expected to be defined in the same library though). Given that
 array libraries don't have to be aware of other types of arrays defined in
-other libraries (see {ref}`assumptions-dependencies`), this should be enough
+other libraries (see :ref:`assumptions-dependencies`), this should be enough
 for a single array library.
 
 That said, an array-consuming library aiming to support multiple array types