Change a little bit the PR template

[mathbagu]

• Please check if the PR fulfills these requirements (please use '[x]' to check the checkboxes, or submit the PR and then click the checkboxes)

• [x] The commit message follows our guidelines

• Does this PR already have an issue describing the problem ? If so, link to this issue using '#XXX' and skip the rest

N/A

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

Contributing

• What is the current behavior? (You can also link to an open issue here)

There are bullets before the questions asked by this template but sometimes it's not really readable (see powsybl-core#710). In this example the list of in the description is followed by the first question of the template

This is an example:

• item 1

• item 2

• Please check if the PR fulfills these requirements (please use '[x]' to check the checkboxes, or submit the PR and then click the checkboxes) ...

• What is the new behavior (if this is a feature change)? With this new version of the template, there is no bullet anymore:

  This is an example:

  • item 1
  • item 2

  Please check if the PR fulfills these requirements (please use '[x]' to check the checkboxes, or submit the PR and then click the checkboxes) ...

• Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?)

I also put the helping messages in italic

• Other information:

(if any of the questions/checkboxes don't apply, please delete them entirely)

[jonenst]

I like it