cmd: Mention that the % must be doubled for FOR variables in batch files. (resubmit)

[Francois Gouget]

Also standardize on the 'Usage:' prefix for usage messages.
---

During the Wine freeze we opted for simply removing the incorrect 
sentence wrt to the % doubling to make it easier to preserve the 
translations.

However I think it's worth having a more complete usage message so I'm 
resubmitting this patch now that there's time to update the translations 
before Wine's next release.

 programs/cmd/cmd.rc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/programs/cmd/cmd.rc b/programs/cmd/cmd.rc
index 69bafc6..e3851ed 100644
--- a/programs/cmd/cmd.rc
+++ b/programs/cmd/cmd.rc
@@ -63,7 +63,9 @@ preceding it with an @ sign.\n"
   WCMD_FOR,
 "The FOR command is used to execute a command for each of a set of files.\n\
 \n\
-Syntax: FOR %variable IN (set) DO command\n"
+Usage: FOR %variable IN (set) DO command\n\
+\n\
+The % sign must be doubled when using FOR in a batch file.\n"
 
   WCMD_GOTO,
 "The GOTO command transfers execution to another statement within a\n\
-- 
1.8.4.rc3