minor #2771 [Map] Remove invalid marker icon example (dannyvw)

This PR was merged into the 2.x branch.

Discussion
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[Map] Remove invalid marker icon example

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Docs?         | no <!-- required for new features -->
| Issues        | Fix #... <!-- prefix each issue number with "Fix #", no need to create an issue if none exist, explain below instead -->
| License       | MIT

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This icon example is invalid and is better described under "Add marker icons".

Commits
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d5c99f9 [Map] Remove invalid marker icon example

Author: Kocal

src/Map/doc/index.rst

@@ -109,10 +109,6 @@ You can add markers to a map using the ``addMarker()`` method::
                 headerContent: '<b>Lyon</b>',
                 content: 'The French town in the historic Rhône-Alpes region, located at the junction of the Rhône and Saône rivers.'
             ),
-            icon: new Icon(
-                content: '<svg>....</svg>'
-                icontType: 'html'
-            )
         ))
 
         // You can also pass arbitrary data via the `extra` option in both the marker