Improve documentation for index pattern custom label (#89137) (#89261)

Co-authored-by: gchaps <33642766+gchaps@users.noreply.github.com>

docs/management/index-patterns.asciidoc

@@ -158,10 +158,13 @@ date values in {es}, you can use a {kib} field formatter to change the display t
 <<field-formatters-geopoint, geopoints>>,
 and <<field-formatters-numeric, numbers>>.
 
+To customize the displayed field name provided by {es}, you can 
+use *Custom Label* .
+
 A popularity counter keeps track of the fields you use most often.
 The top five most popular fields and their values are displayed in <<discover,*Discover*>>.
 
-To edit the field format and popularity counter, click the edit icon
+To edit the field display, click the edit icon
 (image:management/index-patterns/images/edit_icon.png[]) in the index pattern detail view.
 
 [role="screenshot"]

docs/management/managing-fields.asciidoc

@@ -18,6 +18,7 @@ To format a field:
 . Open the main menu, and click *Stack Management > Index Patterns*.
 . Click the index pattern that contains the field you want to format.
 . Find the field you want to format and click the edit icon (image:management/index-patterns/images/edit_icon.png[]).
+. Enter a custom label for the field, if needed.
 . Select a format and fill in the details.
 +
 [role="screenshot"]