Overwork documentation (#3444)

* 📝 overwork macro documentation

* 📝 address review comments

* 🔧 add style check to Makefile

* 🙈 overwork .gitignore

* 📌 Pygments 2.12.0 is broken

* ✏️ fix links

* 🚸 adjust output to cppcheck

* 📝 add titles to more admonitions

* ✏️ fix typos

* 📝 document future behavior change

doc/mkdocs/docs/api/basic_json/operator[].md

@@ -74,10 +74,11 @@ Strong exception safety: if an exception occurs, the original value stays intact
 
 ## Notes
 
-!!! danger
+!!! danger "Undefined behavior and runtime assertions"
 
     1. If the element with key `idx` does not exist, the behavior is undefined.
-    2. If the element with key `key` does not exist, the behavior is undefined and is **guarded by an assertion**!
+    2. If the element with key `key` does not exist, the behavior is undefined and is **guarded by a
+       [runtime assertion](../../features/assertions.md)**!
 
 1. The non-const version may add values: If `idx` is beyond the range of the array (i.e., `idx >= size()`), then the
    array is silently filled up with `#!json null` values to make `idx` a valid reference to the last stored element. In