fix(app): make a backslash before an emoji node keep it literal (#2010)

fluxer_app/src/features/lexical/composer/ComposerMarkdownHighlight.ts

@@ -139,6 +139,16 @@ function $reconcileParagraph(paragraph: ParagraphNode, parserFlags?: number): vo
 	}
 }
 
+function $isEscapedAtOffset(source: string, offset: number): boolean {
+	let backslashes = 0;
+	let cursor = offset - 1;
+	while (cursor >= 0 && source[cursor] === '\\') {
+		backslashes += 1;
+		cursor -= 1;
+	}
+	return backslashes % 2 === 1;
+}
+
 function $reconcileLine(
 	line: Array<LexicalNode>,
 	parserFlags?: number,
@@ -153,13 +163,15 @@ function $reconcileLine(
 		const nodeText = $nodeWireText(node);
 		const nodeEnd = sourceOffset + nodeText.length;
 		if ($isComposerMentionNode(node) || $isComposerCustomEmojiNode(node) || $isComposerStandardEmojiNode(node)) {
-			const literal = spans.some(
-				(span) =>
-					span.role === 'content' &&
-					(span.format & MarkdownHl.code) !== 0 &&
-					span.start <= sourceOffset &&
-					span.end >= nodeEnd,
-			);
+			const literal =
+				$isEscapedAtOffset(source, sourceOffset) ||
+				spans.some(
+					(span) =>
+						span.role === 'content' &&
+						(span.format & MarkdownHl.code) !== 0 &&
+						span.start <= sourceOffset &&
+						span.end >= nodeEnd,
+				);
 			if (node.isLiteral() !== literal) {
 				node.setLiteral(literal);
 			}