[RFA] Improve on-line help for thread_apply_command and thread_apply_all_command.

[Philippe Waroquiers <philippe.waroquiers@skynet.be>]

Add a Usage: line for thread_apply_command, in particular to mention
the thread ID list.

In thread_apply_command and thread_apply_all_command help, use
uppercase for arg names, as this style seems to be more standard.

2018-04-20  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* thread.c (_initialize_thread): improve on-line help for
	thread_apply_command and thread_apply_all_command.
---
 gdb/thread.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/gdb/thread.c b/gdb/thread.c
index 23aa5ba117..a09d7e0ba0 100644
--- a/gdb/thread.c
+++ b/gdb/thread.c
@@ -2028,15 +2028,17 @@ The new thread ID must be currently known."),
 		  &thread_cmd_list, "thread ", 1, &cmdlist);
 
   add_prefix_cmd ("apply", class_run, thread_apply_command,
-		  _("Apply a command to a list of threads."),
+		  _("Apply a command to a list of threads.\n\
+Usage: thread apply ID... COMMAND\n\
+ID is a space-separated list of IDs of threads to apply COMMAND on."),
 		  &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
 
   add_cmd ("all", class_run, thread_apply_all_command,
 	   _("\
 Apply a command to all threads.\n\
 \n\
-Usage: thread apply all [-ascending] <command>\n\
--ascending: Call <command> for all threads in ascending order.\n\
+Usage: thread apply all [-ascending] COMMAND\n\
+-ascending: Call COMMAND for all threads in ascending order.\n\
             The default is descending order.\
 "),
 	   &thread_apply_list);
-- 
2.11.0