Reorganize directories (#3462)

* 🚚 move files
* 🚚 rename doc folder to docs
* 🚚 rename test folder to tests

docs/mkdocs/docs/api/macros/json_noexception.md

@@ -0,0 +1,32 @@
+# JSON_NOEXCEPTION
+
+```cpp
+#define JSON_NOEXCEPTION
+```
+
+Exceptions can be switched off by defining the symbol `JSON_NOEXCEPTION`. When defining `JSON_NOEXCEPTION`, `#!cpp try`
+is replaced by `#!cpp if (true)`, `#!cpp catch` is replaced by `#!cpp if (false)`, and `#!cpp throw` is replaced by
+`#!cpp std::abort()`.
+
+The same effect is achieved by setting the compiler flag `-fno-exceptions`.
+
+## Default definition
+
+By default, the macro is not defined.
+
+```cpp
+#undef JSON_NOEXCEPTION
+```
+
+## Notes
+
+The explanatory [`what()`](https://en.cppreference.com/w/cpp/error/exception/what) string of exceptions is not
+available for MSVC if exceptions are disabled, see [#2824](https://github.com/nlohmann/json/discussions/2824).
+
+## See also
+
+- [Switch off exceptions](../../home/exceptions.md#switch-off-exceptions) for more information how to switch off exceptions
+
+## Version history
+
+Added in version 2.1.0.