Issue template: ask for complete error message

The error messages generated by sharp are designed to provide
people with as much information about the situation as possible.
If someone is asked to copy/paste the error, it's more likely
they might actually read it, which might then allow them to help
themselves without the need to open a new issue.

.github/ISSUE_TEMPLATE/installation.md

@@ -52,6 +52,10 @@ and try again before opening an issue.
 If you cannot confirm any of these, please upgrade to the latest version of your chosen package manager
 and ensure you are allowing the installation of optional or multi-platform dependencies before opening an issue.
 
+### What is the complete error message, including the full stack trace?
+
+<!-- Please provide the error message and stack trace here. -->
+
 ### What is the complete output of running `npm install --verbose --foreground-scripts sharp` in an empty directory?
 
 <details>