Make crash handler tell users to email more detail

Pull request  #11043, to solve issue  #11042.
Taking into account reviewer comments on previous draft.

IPython/core/crashhandler.py

@@ -53,15 +53,15 b" with the subject '{app_name} Crash Report'."
 If you want to do it now, the following command will work (under Unix):
 mail -s '{app_name} Crash Report' {contact_email} < {crash_report_fname}
 
-Please also include in your email:
-- information about your operating system: is it Linux, macOS, Windows, other,
-  and which version, for example Ubuntu 16.04, macOS 10.13.2, Windows 10 Pro,
-  is it 32-bit or 64-bit, ...
-- information on how you installed {app_name}: from binary, compiled from source,
-  via Docker, on a virtual machine...
-- information on how to reproduce the crash: what exact sequence of instructions
-  can one input to get the same crash? Ideally, find a minimal yet complete
-  sequence of instructions that yields the crash.
+In your email, please also include information about:
+- The operating system under which the crash happened: Linux, macOS, Windows,
+  other, and which exact version (for example: Ubuntu 16.04.3, macOS 10.13.2,
+  Windows 10 Pro), and whether it is 32-bit or 64-bit;
+- How {app_name} was installed: using pip or conda, from GitHub, as part of
+  a Docker container, or other, providing more detail if possible;
+- How to reproduce the crash: what exact sequence of instructions can one
+  input to get the same crash? Ideally, find a minimal yet complete sequence
+  of instructions that yields the crash.
 
 To ensure accurate tracking of this issue, please file a report about it at:
 {bug_tracker}