Add RISKS section to Bash tools. Re-order all tools' DOWNLOADING section. Remove some unused options.

bin/pt-stalk

@@ -178,6 +178,25 @@ a script.  By default it executes L<pt-collect>, but that can be customized.
 This tool is useful for gathering diagnostic data when an infrequent event
 occurs, so an expert person can review the data later.
 
+=head1 RISKS
+
+The following section is included to inform users about the potential risks,
+whether known or unknown, of using this tool.  The two main categories of risks
+are those created by the nature of the tool (e.g. read-only tools vs. read-write
+tools) and those created by bugs.
+
+pt-stalk is a read-only tool.  It should be very low-risk.
+
+At the time of this release, we know of no bugs that could cause serious harm
+to users.
+
+The authoritative source for updated information is always the online issue
+tracking system.  Issues that affect this tool will be marked as such.  You can
+see a list of such issues at the following URL:
+L<http://www.percona.com/bugs/pt-stalk>.
+
+See also L<"BUGS"> for more information on filing bugs and getting help.
+
 =head1 DESCRIPTION
 
 Although pt-stalk comes pre-configured to do a specific thing, in general