Update bug report issue template (--diagnostic option)

.github/ISSUE_TEMPLATE/bug_report.md

@@ -9,11 +9,6 @@ assignees: ''
 
 <!-- Hey there, thank you for creating an issue! -->
 
-**What version of `bat` are you using?**
-
-<!-- Output of `bat --version` -->
-
-
 **Describe the bug you encountered:**
 
 ...
@@ -29,19 +24,24 @@ assignees: ''
 
 ---
 
-**Environment**
+**bat version and environment**
 
 <!--
 In order to reproduce your issue, please add some information about the environment
-in which you're running bat.
+in which you're running bat. To do this, run the full `bat` command that demonstrates
+the bug, and attach the `--diagnostic` option:
 
-Linux and MacOS:
-  Please run the script at
+    bat [other options and arguments…] --diagnostic
+
+Finally, paste the Markdown output here. Please make sure that it does not reveal any
+personal information.
+
+
+If you are running bat 0.17.1 or older (where --diagnostic is not available), please
+run the script at
 
     https://github.com/sharkdp/bat/blob/master/diagnostics/info.sh
 
-  (click "Raw" to get the actual source code) and paste the Markdown output here.
-
-Windows:
-  Please add your Windows Version (e.g. "Windows 10 1908")
+(click "Raw" to get the actual source code) and paste the Markdown output here. If you
+are on Windows, please let us know your bat version and your Windows version.
 -->