Fix syntax comments for box-shadow property (mdn#42689)

* Fix syntax comments for box-shadow property

* Update files/en-us/web/css/reference/properties/box-shadow/index.md

Co-authored-by: Dipika Bhattacharya <dipika@foss-community.org>

---------

Co-authored-by: Dipika Bhattacharya <dipika@foss-community.org>

Author: estelle

files/en-us/web/css/reference/properties/box-shadow/index.md

@@ -57,22 +57,18 @@ box-shadow:
 box-shadow: none;
 
 /* A color and two length values */
-/* <color> | <length> | <length> */
 box-shadow: red 60px -16px;
 
 /* Three length values and a color */
-/* <length> | <length> | <length> | <color> */
 box-shadow: 10px 5px 5px black;
 
 /* Four length values and a color */
-/* <length> | <length> | <length> | <length> | <color> */
 box-shadow: 2px 2px 2px 1px rgb(0 0 0 / 20%);
 
 /* inset, length values, and a color */
-/* <inset> | <length> | <length> | <color> */
 box-shadow: inset 5em 1em gold;
 
-/* Any number of shadows, separated by commas */
+/* Multiple shadows, separated by commas */
 box-shadow:
   3px 3px red inset,
   -1em 0 0.4em olive;