doc: fast-import: contextualize the hardware cost

6e411d2 (Initial draft of fast-import documentation., 2007-02-05)
pointed out how much time a fast-import took on some hardware with a
specific cost.  Let’s further point out that this experiment was done
in 2007.  So modern hardware should have no issues with such a repo.

Also move the parenthetical to the end now that it contains four words.

Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: LemmingAvalanche

Documentation/git-fast-import.txt

@@ -182,7 +182,7 @@ amount of memory usage and processing time.  Assuming the frontend
 is able to keep up with fast-import and feed it a constant stream of data,
 import times for projects holding 10+ years of history and containing
 100,000+ individual commits are generally completed in just 1-2
-hours on quite modest (~$2,000 USD) hardware.
+hours on quite modest hardware (~$2,000 USD in 2007).
 
 Most bottlenecks appear to be in foreign source data access (the
 source just cannot extract revisions fast enough) or disk IO (fast-import