Auto merge of #23016 - pngai:remove-on-prefix, r=jdm

Remove 'on' prefix from event handler macros

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Remove 'on' prefix from event handler macros

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #22516 (GitHub issue number if applicable)

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- [X] There are tests for these changes OR
- [ ] These changes do not require tests because ___

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tests/wpt/metadata/html/semantics/embedded-content/media-elements/interfaces/TextTrack/oncuechange.html.ini

@@ -1,4 +0,0 @@
-[oncuechange.html]
-  [TextTrack.oncuechange]
-    expected: FAIL
-

tests/wpt/metadata/html/semantics/embedded-content/media-elements/interfaces/TextTrackList/onaddtrack.html.ini

@@ -1,4 +0,0 @@
-[onaddtrack.html]
-  [TextTrackList.onaddtrack]
-    expected: FAIL
-

tests/wpt/metadata/html/semantics/embedded-content/media-elements/interfaces/TextTrackList/onremovetrack.html.ini

@@ -1,4 +0,0 @@
-[onremovetrack.html]
-  [TextTrackList.onremovetrack]
-    expected: FAIL
-