Fix #182 by changing the styling bits of the shell and text field

[gayanper]

The shell styling is changed to match AbstractInformationControl so the
same styles will get applied from themes. The text style bits are
updated to make it appear same as in different eclipse outline controls.

[sebthom]

@gayanper thanks for your contribution!
would you mind adding two screenshots (before/after) illustrating the effect of your change?

[gayanper]

@gayanper thanks for your contribution!
would you mind adding two screenshots (before/after) illustrating the effect of your change?

Before

After

[gayanper]

@sebthom Any feedback ?

[sebthom]

@gayanper LGTM but I would like to leave the decision to @mickaelistria because of his comment at #182 (comment)

[sebthom]

@mickaelistria WDYT?

[mickaelistria]

I usually prefer sticking to default settings, and consider those discussions in a more global way. I don't think it's (been) a good thing that each project implements slight tweaks over sticking to default. In the end, it brings more inconsistency and more maintenance effort.

[mickaelistria]

The initial target branch master was deleted and replaced by main, so this PR got closed automatically. If this is still relevant, please re-create this PR targetting the main branch.