git-guilt: add page (#10890)

* git-guilt: add page

* git-guilt: fix command placeholders

Co-authored-by: Reinhart Previano Koentjoro <reinhart_previano@yahoo.com>

---------

Co-authored-by: Reinhart Previano Koentjoro <reinhart_previano@yahoo.com>

pages/common/git-guilt.md

@@ -0,0 +1,29 @@
+# git guilt
+
+> Show total blame count for files with unstaged changes or calculate the change in blame between two revisions.
+> Part of `git-extras`.
+> More information: <https://github.com/tj/git-extras/blob/master/Commands.md#git-guilt>.
+
+- Show total blame count:
+
+`git guilt`
+
+- Calculate the change in blame between two revisions:
+
+`git guilt {{first_revision}} {{last_revision}}`
+
+- Show author emails instead of names:
+
+`git guilt --email`
+
+- Ignore whitespace only changes when attributing blame:
+
+`git guilt --ignore-whitespace`
+
+- Find blame delta over the last three weeks:
+
+`git guilt 'git log --until="3 weeks ago" --format="%H" -n 1'`
+
+- Find blame delta over the last three weeks (git 1.8.5+):
+
+`git guilt @{3.weeks.ago}`