TypeScript: add "bigint" primitive type
Summary: Add the "bigint" type: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-2.html#bigint
Reviewers: Framework: Syntax Highlighting, cullmann
Reviewed By: Framework: Syntax Highlighting, cullmann
Subscribers: cullmann, kwrite-devel, kde-frameworks-devel
Tags: Kate, Frameworks
Differential Revision: https://phabricator.kde.org/D25939