Modify Commit Message Dialog

[JansenSmith]

Overall goal is to include the filename in the publish UI and standardize the UI language to all reference publishing (except solely in the instructions, which focus on what the action is DOING).

• rename box from "Commit message Dialog" to "Publish file to GitHub"
• rename instructions from "Enter a commit message to publish changes" to "Enter a commit message to push changes for file "
• rename tooltip from "Save this code to Git" to "Publish this file to GitHub"