Clarify Symbol.toPrimitive example (fixes nzakas#374)

Author: nzakas

manuscript/06-Symbols.md

@@ -388,7 +388,7 @@ The `hasLengthOf10` object is intended to work like a regular expression that ma
 
 While this is a simple example, the ability to perform more complex matches than are currently possible with regular expressions opens up a lot of possibilities for custom pattern matchers.
 
-### The Symbol.toPrimitive Symbol
+### The Symbol.toPrimitive Method
 
 JavaScript frequently attempts to convert objects into primitive values implicitly when certain operations are applied. For instance, when you compare a string to an object using the double equals (`==`) operator, the object is converted into a primitive value before comparing. Exactly what primitive value should be used was previously an internal operation, but ECMAScript 6 exposes that value (making it changeable) through the `Symbol.toPrimitive` method.
 
@@ -438,7 +438,7 @@ console.log(freezing / 2);              // 16
 console.log(String(freezing));          // "32°"
 ```
 
-This script defines a `Temperature` constructor and overrides the default `Symbol.toPrimitive` method on the prototype. A different value is returned depending on whether the `hint` argument indicates string, number, or default mode (the `hint` argument is filled in by the JavaScript engine). In string mode, the `Temperature()` function returns the temperature with the Unicode degrees symbol. In number mode, it returns just the numeric value, and in default mode, it appends the word "degrees" after the number.
+This script defines a `Temperature` constructor and overrides the default `Symbol.toPrimitive` method on the prototype. A different value is returned depending on whether the `hint` argument indicates string, number, or default mode (the `hint` argument is filled in by the JavaScript engine). In string mode, the `Symbol.toPrimitive` method returns the temperature with the Unicode degrees symbol. In number mode, it returns just the numeric value, and in default mode, it appends the word "degrees" after the number.
 
 Each of the log statements triggers a different `hint` argument value. The `+` operator triggers default mode by setting `hint` to `"default"`, the `/` operator triggers number mode by setting `hint` to `"number"`, and the `String()` function triggers string mode by setting `hint` to `"string"`. Returning different values for all three modes is possible, it's much more common to set the default mode to be the same as string or number mode.