Update FlashMigrationCounter guidance to reference un-deprecated component (#3694)

Author: tomthorogood

lib/primer/view_components/linters/flash_migration_counter.rb

@@ -12,9 +12,9 @@ class FlashMigrationCounter < BaseLinter
 
       TAGS = %w[div].freeze
       CLASSES = %w[flash].freeze
-      MESSAGE = "We are migrating flashes to use [Primer::Beta::Flash](https://primer.style/view-components/components/beta/flash), please try to use that instead of raw HTML."
+      MESSAGE = "We are migrating flashes to use [Primer::Alpha::Banner](https://primer.style/view-components/components/alpha/banner), please try to use that instead of raw HTML."
       ARGUMENT_MAPPER = ArgumentMappers::Flash
-      COMPONENT = "Primer::Beta::Flash"
+      COMPONENT = "Primer::Alpha::Banner"
 
       def map_arguments(tag, tag_tree)
         # We can only autocorrect elements with simple text as content.

test/lib/erblint/flash_migration_counter_test.rb

@@ -10,7 +10,7 @@ def test_suggests_how_to_use_the_component_with_arguments
     @file = "<div class=\"flash flash-warn flash-full\">flash</div>"
     @linter.run(processed_source)
 
-    assert_includes(offenses.first.message, "render Primer::Beta::Flash.new(scheme: :warning, full: true)")
+    assert_includes(offenses.first.message, "render Primer::Alpha::Banner.new(scheme: :warning, full: true)")
   end
 
   def test_does_not_autocorrect_with_html_content