correct the translation of number in equality.md

In equality.md,

```
Additionally, there is also a performance impact when type coercion is in play;
for example, a string has to be converted to a number before it can be compared
to another number.
```
was translated to:
```
此外，强制类型转换也会带来性能消耗，比如一个字符串为了和一个数组进行比较，必须事先被强制转换为数字。
```
in which `number` should be translated to `数字` instead of  `数组`. Here it is:


```
此外，强制类型转换也会带来性能消耗，比如一个字符串为了和一个数字进行比较，必须事先被强制转换为数字。
```