added premake manager extension to extensions.md (#2455)

* added premake manager extension to extensions.md

* added VSPremake and added extensions to the sidebar

* fixed type in extensions.md

---------

Co-authored-by: Beernaert Robbe <robbe.beernaert@student.howest.be>

Author: lolrobbe2

website/community/extensions.md

@@ -0,0 +1,13 @@
+---
+title: Extensions
+---
+
+These IDE extensions are available from other developers; follow the links for more information. If you've developed an extension you would like to share with others, feel free to [add a link](https://github.com/premake/premake-core/edit/master/website/community/extensions.md) to the list!
+
+## Visual Studio Code
+
+- [Premake Manager](https://marketplace.visualstudio.com/items?itemName=lolrobbe2.premake-manager) : Manage premake projects and use the integrated premake terminal.
+
+## Visual Studio
+
+- [VSPremake](https://marketplace.visualstudio.com/items?itemName=ColtonMcGraw.VSPremake) : Run Premake5 inside Visual Studio

website/sidebars-community.js

@@ -2,6 +2,7 @@ module.exports = {
 	community: [
 		'support',
 		'showcase',
+		'extensions',
 		'modules'
 	]
 };