Small help text fixes, to make it more consistent and accurate.

Temporarily remove -l option from 'expr' command (at Sean's request).

llvm-svn: 113298
diff --git a/lldb/source/Commands/CommandObjectSource.cpp b/lldb/source/Commands/CommandObjectSource.cpp
index 6f83e2b..937e624 100644
--- a/lldb/source/Commands/CommandObjectSource.cpp
+++ b/lldb/source/Commands/CommandObjectSource.cpp
@@ -575,7 +575,7 @@
 
 CommandObjectMultiwordSource::CommandObjectMultiwordSource (CommandInterpreter &interpreter) :
     CommandObjectMultiword ("source",
-                            "Commands for accessing source file information",
+                            "A set of commands for accessing source file information",
                             "source <subcommand> [<subcommand-options>]")
 {
     LoadSubCommand (interpreter, "info",   CommandObjectSP (new CommandObjectSourceInfo ()));