Addition of "git commit --amend" command in Text Index of Appendices chapter

[stevensonmichel]

Issue: Normally, certain keywords are referred back in the Text Index section of the Appendices chapter. It is a valuable and convenient way to provide users of the Open Source book the opportunity to see definitions of keywords without having to look for chapters and sections. The Text Index section plays the role of a Thesaurus, where any user can look for words which are sorted in alphabetical order. However, some of the important terminologies of the section 4.5, namely "git commit --amend", were still not in the Text Index section.

Solution: To add the "git commit --amend" section to the Text Index section, we just had to add a new add named "name of the section we want to add" below the tag that initiates that section in the pretext file "sec_git_undoing.ptx". In that case, when the pretext file is rendered, the keyword "git commit --amend" will be created, placed in the right alphabetical order, and it will refer to the section 4.5 of the book that gives a more explanatory approach of the term.

Test: After the initial setup and installation, one would have to not only look at the file "sec_git_undoing.ptx" to look for any flaw. Then, use the building and viewing command to open the book to your localhost inside your browser. There, you can direct yourself to the Text Index section and inspect the section "git commit --amend".

[pearcej]

@stevensonmichel I don't think this is a good fit for the index because then all of the git commands would have to go threre. I do think it would be a nice addition to the git cheatsheet

[stevensonmichel]

I just fix that by incorporating the "git commit --amend" in the Git Cheat Sheet section. In addition, I added a new section inside the Git Cheat Sheet about Git Restoring/Reverting

[pearcej]

@stevensonmichel This is superbly done. An exemplary issue followed by an excellent set of changes. Bravo!