Apply few changes

[amiralisahraei]

Hello. The list of changes is as follows.

1. No need to add "git" in double quotation when you want to set alias.
2. Add 'filename' when use 'restore'.
3. Add a table to compare 'git revert' and 'git reset'.
4. Add comment for 'git branch -d branch_name'.
5. Add 'git diff branch1..branch2' to show the differences between the two branches.
6. Remove '>> git ignore' because there is not command like this in git.
7. Add 'git checkout '.
8. Add 'git rm filename'.
9. Capitalize 'head'.