SQUASHME docs/yul: replace all code with code-block

Surfaced:

    Warning, treated as error:
    /root/project/docs/yul.rst:130:Could not lex literal_block as "yul". Highlighting skipped.

Line 130 is the JSON code block. :/

Strange: is this because of `highlight` being `yul` instead of
`Yul`?..

docs/yul.rst

@@ -117,7 +117,7 @@ This will use the :ref:`Yul object notation <yul-object>` so that it is possible
 to code as data to deploy contracts. This Yul mode is available for the commandline compiler
 (use ``--strict-assembly``) and for the :ref:`standard-json interface <compiler-api>`:
 
-.. code:: json
+.. code-block:: json
 
     {
         "language": "Yul",
@@ -182,14 +182,14 @@ bitwise ``and`` with the string "abc" is computed.
 The final value is assigned to a local variable called ``x``.
 Strings are stored left-aligned and cannot be longer than 32 bytes.
 
-.. code::
+.. code-block::
 
     let x := and("abc", add(3, 2))
 
 Unless it is the default type, the type of a literal
 has to be specified after a colon:
 
-.. code::
+.. code-block::
 
     let x := and("abc":uint32, add(3:uint256, 2:uint256))
 
@@ -203,7 +203,7 @@ If the function returns a single value, it can be directly used
 inside an expression again. If it returns multiple values,
 they have to be assigned to local variables.
 
-.. code::
+.. code-block::
 
     mstore(0x80, add(mload(0x80), 3))
     // Here, the user-defined function `f` returns
@@ -244,7 +244,7 @@ Future dialects migh introduce specific types for such pointers.
 When a variable is referenced, its current value is copied.
 For the EVM, this translates to a ``DUP`` instruction.
 
-.. code::
+.. code-block::
 
     {
         let zero := 0
@@ -262,7 +262,7 @@ you denote that following a colon. You can also declare multiple
 variables in one statement when you assign from a function call
 that returns multiple values.
 
-.. code::
+.. code-block::
 
     {
         let zero:uint32 := 0:uint32
@@ -285,7 +285,7 @@ values have to match.
 If you want to assign the values returned from a function that has
 multiple return parameters, you have to provide multiple variables.
 
-.. code::
+.. code-block::
 
     let v := 0
     // re-assign v
@@ -303,7 +303,7 @@ The if statement can be used for conditionally executing code.
 No "else" block can be defined. Consider using "switch" instead (see below) if
 you need multiple alternatives.
 
-.. code::
+.. code-block::
 
     if eq(value, 0) { revert(0, 0) }
 
@@ -319,7 +319,7 @@ Contrary to other programming languages, for safety reasons, control flow does
 not continue from one case to the next. There can be a fallback or default
 case called ``default`` which is taken if none of the literal constants matches.
 
-.. code::
+.. code-block::
 
     {
         let x := 0
@@ -351,7 +351,7 @@ or skip to the post-part, respectively.
 
 The following example computes the sum of an area in memory.
 
-.. code::
+.. code-block::
 
     {
         let x := 0
@@ -363,7 +363,7 @@ The following example computes the sum of an area in memory.
 For loops can also be used as a replacement for while loops:
 Simply leave the initialization and post-iteration parts empty.
 
-.. code::
+.. code-block::
 
     {
         let x := 0
@@ -406,7 +406,7 @@ the current yul function.
 
 The following example implements the power function by square-and-multiply.
 
-.. code::
+.. code-block::
 
     {
         function power(base, exponent) -> result {
@@ -929,7 +929,7 @@ Above, ``Block`` refers to ``Block`` in the Yul code grammar explained in the pr
 
 An example Yul Object is shown below:
 
-.. code::
+.. code-block::
 
     // A contract consists of a single object with sub-objects representing
     // the code to be deployed or other contracts it can create.
@@ -1012,7 +1012,7 @@ for more details about its internals.
 
 If you want to use Solidity in stand-alone Yul mode, you activate the optimizer using ``--optimize``:
 
-.. code:: sh
+.. code-block:: sh
 
     solc --strict-assembly --optimize