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/basic_json/find.md

@@ -1,11 +1,11 @@
-# basic_json::find
+# <small>nlohmann::basic_json::</small>find
 
 ```cpp
 template<typename KeyT>
 iterator find(KeyT&& key);
 
 template<typename KeyT>
-const_iterator find(KeyT&& key) const
+const_iterator find(KeyT&& key) const;
 ```
 
 Finds an element in a JSON object with key equivalent to `key`. If the element is not found or the JSON value is not an
@@ -38,7 +38,7 @@ Logarithmic in the size of the JSON object.
 
 This method always returns `end()` when executed on a JSON type that is not an object.
 
-## Example
+## Examples
 
 ??? example
 
@@ -54,6 +54,10 @@ This method always returns `end()` when executed on a JSON type that is not an o
     --8<-- "examples/find__key_type.output"
     ```
 
+## See also
+
+- [contains](contains.md) checks whether a key exists
+
 ## Version history
 
 - Added in version 1.0.0.