Update introduction.md (#2205)

Fix sentence so that it makes more sense.

concepts/chars/introduction.md

@@ -5,7 +5,7 @@ Multiple `char`s can comprise a string such as `"word"` or `char`s can be
 processed independently. Their literals have single quotes e.g. `'A'`.
 
 C# `char`s support UTF-16 Unicode encoding so in addition to the latin character set
-pretty much all the writing systems in use world can be represented,
+pretty much all the writing systems used worldwide can be represented,
 e.g. the Greek letter `'β'`.
 
 There are many builtin library methods to inspect and manipulate `char`s. These