Add note in Revision Selection about PowerShell

I've been struggling with the revision selection syntax `HEAD@{...}` and finally found out it's because of curly braces special meaning in PowerShell.

I noticed the NOTE on special handling of caret in cmd.exe on Windows. A similar note about curly braces in PowerShell would have saved me some time and I hope to save fellow developers some time by adding in such a note.

Thanks to HonkingGoose for his minor changes.

Co-authored-by: HonkingGoose <[email protected]>

Author: 2 people

book/07-git-tools/sections/revision-selection.asc

@@ -180,6 +180,22 @@ Running `git show HEAD@{2.months.ago}` will show you the matching commit only if
 If you have a UNIX or Linux background, you can think of the reflog as Git's version of shell history, which emphasizes that what's there is clearly relevant only for you and your ``session'', and has nothing to do with anyone else who might be working on the same machine.
 ====
 
+[NOTE]
+.Escaping brackets in PowerShell
+====
+
+On Windows in `powershell.exe`, `{` and `}` are special characters and needs to be treated differently.
+You can either escape them with a backtick ` or put the commit reference in quotes:
+
+[source,console]
+----
+$ git show HEAD@{0}     # will NOT work on Windows
+$ git show HEAD@`{0`}   # OK
+$ git show "HEAD@{0}"   # OK
+----
+
+====
+
 ==== Ancestry References
 
 The other main way to specify a commit is via its ancestry.