update whatsnew for (# 21237)

peterpanmj · peterpanmj · commit fd1cb9675baf · 2018-06-04T21:47:41.000+08:00
diff --git a/doc/source/whatsnew/v0.24.0.txt b/doc/source/whatsnew/v0.24.0.txt
@@ -63,7 +63,7 @@ Removal of prior version deprecations/changes
 Performance Improvements
 ~~~~~~~~~~~~~~~~~~~~~~~~
 
--
+- Improved performance of :func:`pandas.core.groupby.GroupBy.rank` (:issue:`21237`)
 -
 -
 

Original file line number	Diff line number	Diff line change
`@@ -63,7 +63,7 @@ Removal of prior version deprecations/changes`
`63`	`63`	`Performance Improvements`
`64`	`64`	`~~~~~~~~~~~~~~~~~~~~~~~~`
`65`	`65`
`66`		`--`
	`66`	+- Improved performance of :func:`pandas.core.groupby.GroupBy.rank` (:issue:`21237`)
`67`	`67`	`-`
`68`	`68`	`-`
`69`	`69`