fix: prevent duplicate reason(microsoft#186206)

Author: yshaojun

src/vs/editor/contrib/unicodeHighlighter/browser/unicodeHighlighter.ts

@@ -429,6 +429,7 @@ export class UnicodeHighlighterHoverParticipant implements IEditorHoverParticipa
 		}
 
 		const result: MarkdownHover[] = [];
+		const existedReason = new Map<string, boolean>();
 		let index = 300;
 		for (const d of lineDecorations) {
 
@@ -480,6 +481,11 @@ export class UnicodeHighlighterHoverParticipant implements IEditorHoverParticipa
 					break;
 			}
 
+			if (existedReason.has(reason)) {
+				continue;
+			}
+			existedReason.set(reason, true);
+
 			const adjustSettingsArgs: ShowExcludeOptionsArgs = {
 				codePoint: codePoint,
 				reason: highlightInfo.reason,