PULL_REQUEST_TEMPLATE.md

Description

[Describe your changes in detail]

Motivation and Context

[Why is this change required? What problem does it solve?]

[If it fixes an open issue, please link to the issue here by writing "Closes #XXX"]

Screenshots (if appropriate):

[You can use Windows+Shift+S or Control+Command+Shift+4 to add a screenshot to your clipboard and then paste it here.]

Checklist:

• I have updated the documentation, as applicable.
• I have updated the theme.toml, as applicable.