docs(igx-date-range-picker): fix igxDateRange name (#7372)

Author: Lipata

CHANGELOG.md

@@ -38,7 +38,7 @@ All notable changes for each version of this project will be documented in this
     ```
 - `IgxDateRangePicker` component added.
     - Allows the selection of a range of dates from a calendar UI or input fields. Supports `dialog` and `dropdown` modes.
-    - Added `IgxDateStartComponent` and `IgxDateEndComponent`.
+    - Added `IgxDateRangeStartComponent` and `IgxDateRangeEndComponent`.
     - The default template consists of a single *readonly* field:
     ```html
     <igx-date-range-picker [(ngModel)]="range"></igx-date-range-picker>

projects/igniteui-angular/src/lib/date-range-picker/README.md

@@ -51,7 +51,7 @@ The default initialization produces a single *readonly* input:
 <igx-date-range-picker [(ngModel)]="range"></igx-date-range-picker>
 ```
 
-With `IgxDateStartComponent`, `IgxDateEndComponent` and `IgxDateTimeEditorDirective` two *editable* inputs can be projected:
+With `IgxDateRangeStartComponent`, `IgxDateRangeEndComponent` and `IgxDateTimeEditorDirective` two *editable* inputs can be projected:
 ```html
 <igx-date-range-picker>
     <igx-date-range-start>