Italicize a variable name in chapter 3

Author: marijnh

03_functions.md

@@ -730,7 +730,7 @@ hint}}
 
 {{index "bean counting (exercise)", [string, indexing], "zero-based counting", ["length property", "for string"]}}
 
-You can get the Nth character, or letter, from a string by writing `[N]` after the string (for example, `string[2]`). The resulting value will be a string containing only one character (for example, `"b"`). The first character has position 0, which causes the last one to be found at position `string.length - 1`. In other words, a two-character string has length 2, and its characters have positions 0 and 1.
+You can get the *N*th character, or letter, from a string by writing `[N]` after the string (for example, `string[2]`). The resulting value will be a string containing only one character (for example, `"b"`). The first character has position 0, which causes the last one to be found at position `string.length - 1`. In other words, a two-character string has length 2, and its characters have positions 0 and 1.
 
 Write a function `countBs` that takes a string as its only argument and returns a number that indicates how many uppercase B characters there are in the string.