Lower and Upper case keyboard letters

In https://github.com/swcarpentry/git-novice/pull/570, @M4rkD changed

```
To get out of the pager, press Q.
```

to

```
To get out of the pager, press q.
```

because on her words

> N searches in reverse when using less, this brings up the confusing message that no matches are found (unless the user has already previously pressed n). The key for searching forward is lowercase n.

She is right about the different behaviour of lower and upper case "n" but the change impact our lesson style guide. When I wrote our recommendation, I intended that we would use `Q` when pressing the key "q" on the keyboard and use `Shift+Q` when we need the shift key, e.g. for a upper case "q". This is to be compatible with the use of other keys, e.g. Alt and Ctrl. What are your impressions?