👾 add mdn links to Map and Set methods

Author: Rnbsov

1-js/05-data-types/07-map-set/article.md

@@ -15,12 +15,12 @@ But that's not enough for real life. That's why `Map` and `Set` also exist.
 Methods and properties are:
 
 - `new Map()` -- creates the map.
-- `map.set(key, value)` -- stores the value by the key.
-- `map.get(key)` -- returns the value by the key, `undefined` if `key` doesn't exist in map.
-- `map.has(key)` -- returns `true` if the `key` exists, `false` otherwise.
-- `map.delete(key)` -- removes the value by the key.
-- `map.clear()` -- removes everything from the map.
-- `map.size` -- returns the current element count.
+- [`map.set(key, value)`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/set) -- stores the value by the key.
+- [`map.get(key)`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/get) -- returns the value by the key, `undefined` if `key` doesn't exist in map.
+- [`map.has(key)`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/has) -- returns `true` if the `key` exists, `false` otherwise.
+- [`map.delete(key)`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/delete) -- removes the value by the key.
+- [`map.clear()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/clear) -- removes everything from the map.
+- [`map.size`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/size) -- returns the current element count.
 
 For instance:
 
@@ -105,9 +105,9 @@ map.set('1', 'str1')
 
 For looping over a `map`, there are 3 methods:
 
-- `map.keys()` -- returns an iterable for keys,
-- `map.values()` -- returns an iterable for values,
-- `map.entries()` -- returns an iterable for entries `[key, value]`, it's used by default in `for..of`.
+- [`map.keys()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/keys) -- returns an iterable for keys,
+- [`map.values()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/values) -- returns an iterable for values,
+- [`map.entries()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/entries) -- returns an iterable for entries `[key, value]`, it's used by default in `for..of`.
 
 For instance: