user-manual: remove temporary branch entry from todo list

In the section on "How to check out a different version of a
project" the "new" branch is used as a temporary branch.  A detached
HEAD was not used since it was a new feature introduced just a
couple weeks prior.

The section could be changed to use and explain a detached HEAD,
except that would increase the learning curve early in the manual.
Detached HEADs are discussed a couple sections later under
"Examining an old version without creating a new branch".

Let's declare that it is a bad idea to rewrite the example that
uses a temporary branch to do the sightseeing on a detached HEAD.

Signed-off-by: Stephen P. Smith <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: Stephen P. Smith

Documentation/user-manual.txt

@@ -4636,9 +4636,6 @@ Scan email archives for other stuff left out
 Scan man pages to see if any assume more background than this manual
 provides.
 
-Simplify beginning by suggesting disconnected head instead of
-temporary branch creation?
-
 Add more good examples.  Entire sections of just cookbook examples
 might be a good idea; maybe make an "advanced examples" section a
 standard end-of-chapter section?