typo

[Jianru-Lin]

The following sections need to be updated when adding a unikernel solution to this repository:

• Table of Contents
• Existing projects
• Comparing Solutions

Examples:

• https://github.com/cetic/unikernels/commit/b67aab5265bd58bb4c19b4560a85d55925a15904
• https://github.com/cetic/unikernels/commit/91bf2fda79634b0cefe7b8a2c197ecef05b87378

[banzo]

Thanks!