Trivial Wording Fix for Introduction (#363)

* Trivial Wording Fix for Introduction

Addresses #362

* English Fixes

Author: ReignOfComputer

src/components/Playground.tsx

@@ -14,7 +14,7 @@ import ListVisualizer from './workspace/side-content/ListVisualizer'
 const CHAP = '\xa7'
 
 const INTRODUCTION = `
-Welcome to the source-academy playground!
+Welcome to the Source Academy playground!
 
 The language _Source_ is the official language of the textbook _Structure and
 Interpretation of Computer Programs, JavaScript Adaptation_. You have never
@@ -25,7 +25,7 @@ the respective textbook chapter. For example, Source ${CHAP}3 is suitable for
 textbook Chapter 3 and the preceeding chapters.
 
 The playground comes with an editor and a REPL, on the left and right of the
-screen, respectively. You may customimse the layout of the playground by
+screen, respectively. You may customise the layout of the playground by
 clicking and dragging on the right border of the editor, or the top border of
 the REPL.
 `