Added octicon to failure message for file preview
Added octicon to failure message for file preview

noellekimiko/HMC-Grader,noellekimiko/HMC-Grader,noellekimiko/HMC-Grader,CSGreater-Developers/HMC-Grader,noellekimiko/HMC-Grader,noellekimiko/HMC-Grader,CSGreater-Developers/HMC-Grader,CSGreater-Developers/HMC-Grader,CSGreater-Developers/HMC-Grader,noellekimiko/HMC-Grader,CSGreater-Developers/HMC-Grader