Remove polish translation

Remove link to polish translation as it's outdated ( last commit from 2-3 years ago ). 
For example in polish translation you can read that you should use one "var" keyword to declare your vars.
example:
```js
// źle ( bad )
var items = getItems();
var goSportsTeam = true;
var dragonball = 'z';

// dobrze ( good )
var items = getItems(),
    goSportsTeam = true,
    dragonball = 'z';
```

Author: marhub

README.md

@@ -3367,7 +3367,6 @@ Other Style Guides
   - ![it](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Italy.png) **Italian**: [sinkswim/javascript-style-guide](https://github.com/sinkswim/javascript-style-guide)
   - ![jp](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Japan.png) **Japanese**: [mitsuruog/javascript-style-guide](https://github.com/mitsuruog/javascript-style-guide)
   - ![kr](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/South-Korea.png) **Korean**: [tipjs/javascript-style-guide](https://github.com/tipjs/javascript-style-guide)
-  - ![pl](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Poland.png) **Polish**: [mjurczyk/javascript](https://github.com/mjurczyk/javascript)
   - ![ru](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Russia.png) **Russian**: [leonidlebedev/javascript-airbnb](https://github.com/leonidlebedev/javascript-airbnb)
   - ![es](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Spain.png) **Spanish**: [paolocarrasco/javascript-style-guide](https://github.com/paolocarrasco/javascript-style-guide)
   - ![th](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Thailand.png) **Thai**: [lvarayut/javascript-style-guide](https://github.com/lvarayut/javascript-style-guide)