Salesforce Tricks : Add line break to Tool tips or field-level help in Lightning Experience.

 A tool tip of a field can be difficult to read when there is no line break.

In formula , we can use "BR()" , but in tool tip, there is no formal method
The idea is still in Idea Exchange .

And a user posted a workaround here , using the "Japanese full width space" (\u3000).

Copy this :   [　　　　　　　　　　]

And put above bracket into the Help text where you need the line break. 

For example:
My line 1 [　　　　　　　　　　] My line 2

Magic is done.