docs(tooltip): fix directive name

Closes #4864

Author: icfantv

src/tooltip/docs/readme.md

@@ -10,7 +10,7 @@ There are three versions of the tooltip: `uib-tooltip`, `uib-tooltip-template`,
 - `uib-tooltip-html` takes
   whatever HTML is provided and displays it in a tooltip; *The user is responsible for ensuring the
   content is safe to put into the DOM!*
-- `uib-tooltip-html-unsafe` -- deprecated in favour of `tooltip-html`
+- `uib-tooltip-html-unsafe` -- deprecated in favour of `uib-tooltip-html`
 
 The tooltip directives provide several optional attributes to control how they
 will display: