Fix mark file as viewed from editor toolbar and keybinding (#6021)

Fixes #6012

Author: alexr00

src/common/utils.ts

@@ -114,13 +114,13 @@ function isWindowsPath(path: string): boolean {
 	return /^[a-zA-Z]:\\/.test(path);
 }
 
-export function isDescendant(parent: string, descendant: string): boolean {
+export function isDescendant(parent: string, descendant: string, separator: string = sep): boolean {
 	if (parent === descendant) {
 		return true;
 	}
 
-	if (parent.charAt(parent.length - 1) !== sep) {
-		parent += sep;
+	if (parent.charAt(parent.length - 1) !== separator) {
+		parent += separator;
 	}
 
 	// Windows is case insensitive

src/github/pullRequestModel.ts

@@ -1933,7 +1933,7 @@ export class PullRequestModel extends IssueModel<PullRequest> implements IPullRe
 
 		const allFilenames = filePathOrSubpaths
 			.map((f) =>
-				isDescendant(this.githubRepository.rootUri.path, f)
+				isDescendant(this.githubRepository.rootUri.path, f, '/')
 					? f.substring(this.githubRepository.rootUri.path.length + 1)
 					: f
 			);