fix syntax highlighting in code examples from other languages

Author: adqm

peps/pep-0798.rst

@@ -746,45 +746,65 @@ to what is already available in Python, but support for using unpacking syntax
 within comprehensions is rare.  This section provides a brief summary of
 support for similar syntax in a few other languages.
 
-Many languages that support comprehensions support double loops::
+Many languages that support comprehensions support double loops:
+
+.. code:: python
 
     # python
     [x for xs in [[1,2,3], [], [4,5]] for x in xs * 2]
 
+.. code:: haskell
+
     -- haskell
     [x | xs <- [[1,2,3], [], [4,5]], x <- xs ++ xs]
 
+.. code:: julia
+
     # julia
     [x for xs in [[1,2,3], [], [4,5]] for x in [xs; xs]]
 
+.. code:: clojure
+
     ; clojure
     (for [xs [[1 2 3] [] [4 5]] x (concat xs xs)] x)
 
 Several other languages (even those without comprehensions) support these
 operations via a built-in function/method to support flattening of nested
-structures::
+structures:
+
+.. code:: python
 
     # python
     list(itertools.chain(*(xs*2 for xs in [[1,2,3], [], [4,5]])))
 
+.. code:: javascript
+
     // Javascript
     [[1,2,3], [], [4,5]].flatMap(xs => [...xs, ...xs])
 
+.. code:: haskell
+
     -- haskell
     concat (map (\x -> x ++ x) [[1,2,3], [], [4,5]])
 
+.. code:: ruby
+
     # ruby
     [[1, 2, 3], [], [4, 5]].flat_map {|e| e * 2}
 
 However, languages that support both comprehension and unpacking do not tend to
 allow unpacking within a comprehension.  For example, the following expression
-in Julia currently leads to a syntax error::
+in Julia currently leads to a syntax error:
+
+.. code:: julia
 
     [xs... for xs in [[1,2,3], [], [4,5]]]
 
 As one counterexample, support for a similar syntax was recently added to `Civet
 <https://civet.dev/>`_.  For example, the following is a valid comprehension in
-Civet, making use of Javascript's ``...`` syntax for unpacking::
+Civet, making use of Javascript's ``...`` syntax for unpacking:
+
+.. code:: javascript
 
     for xs of [[1,2,3], [], [4,5]] then ...(xs++xs)