Add overloading to get method

e.g.

```ts
$("a[href]").map((index, element) => $(element).attr("href")).get();
```

it returns an array of strings

cheerio/cheerio.d.ts

@@ -106,6 +106,7 @@ interface Cheerio {
 
     eq(index: number): Cheerio;
 
+    get(): string[];
     get(): CheerioElement[];
     get(index: number): CheerioElement;