Consolidate documentation (#3071)

* 🔥 consolidate documentation
* ♻️ overwork std specializations
* 🚚 move images files to mkdocs
* ♻️ fix URLs
* 🔧 tweak MkDocs configuration
* 🔧 add namespaces
* 📝 document deprecations
* 📝 document documentation generation
* 🚸 improve search
* 🚸 add examples
* 🚧 start adding documentation for macros
* 📝 add note for https://github.com/nlohmann/json/issues/874#issuecomment-1001699139
* 📝 overwork example handling
* 📝 fix Markdown tables

doc/mkdocs/docs/api/json_pointer/index.md

@@ -0,0 +1,36 @@
+# <small>nlohmann::</small>json_pointer
+
+```cpp
+template<typename BasicJsonType>
+class json_pointer;
+```
+
+A JSON pointer defines a string syntax for identifying a specific value within a JSON document. It can be used with
+functions [`at`](../basic_json/at.md) and [`operator[]`](../basic_json/operator%5B%5D.md). Furthermore, JSON pointers
+are the base for JSON patches.
+
+## Template parameters
+
+`BasicJsonType`
+:   a specialization of [`basic_json`](../basic_json/index.md)
+
+## Member functions
+
+- [(constructor)](json_pointer.md)
+- [**to_string**](to_string.md) - return a string representation of the JSON pointer
+- [**operator std::string**](operator_string.md) - return a string representation of the JSON pointer
+- [**operator/=**](operator_slasheq.md) - append to the end of the JSON pointer
+- [**operator/**](operator_slash.md) - create JSON Pointer by appending
+- [**parent_pointer**](parent_pointer.md) - returns the parent of this JSON pointer
+- [**pop_back**](pop_back.md) - remove last reference token
+- [**back**](back.md) - return last reference token
+- [**push_back**](push_back.md) - append an unescaped token at the end of the pointer
+- [**empty**](empty.md) - return whether pointer points to the root document
+
+## See also
+
+- [RFC 6901](https://datatracker.ietf.org/doc/html/rfc6901)
+
+## Version history
+
+Added in version 2.0.0.