Clarifying the issue template

[schtandard]

I recently opened two issues, one bug report (#917) and one feature request (#918). Both of them were quickly converted to discussions and I was sternly reprimanded for diverging from the issue template and accused of not reading it.

In fact, I did read it and even had a look at the other open issues for reference, none of which adhered to the template. Admittedly, I missed the distinction between feature requests going to discussions and only bugs going to issues. The text seemed to be entirely focused on avoiding support requests, which I did not have. (The distinction is stated more clearly in CONTRIBUTING.md, but I did not read it carefully again, since this was only required for first reporters and I was, though mistaken, not in doubt if the feature request should be an issue.)

In order to avoid situations like this for future reporters, I suggest the following clarifications in the template:

• Replace "Use the mailing list or GitHub discussions page for questions about lmfit or things you think might be problems." by "Use the mailing list or GitHub discussions page for feature requests, questions about lmfit or things you think might be problems.", i.e. explicitly mention feature requests.
• Replace "may" by "will" in "If you delete any of these sections, your Issue may be closed."
• Append "even for the First Time Issue Code" to "If you think one of the sections does not apply to your Issue, state that explicitly." As is, the presence of that section (in combination with the format of the existing issues) suggested to me that the strictness of the template is somewhat relaxed for non-first reporters.
• If the instructions themselves are to be preserved in the finished issue, as is suggested by this comment, this should also be stated explicitly.