Inconsistent tooltips in the edit toolbar

[richlv]

The tooltips for the buttons in the "edit toolbar" are inconsistent in some cases.
Some of these inconsistencies seem to be from the core functionality, some from plugins.
Observed in the Mac version 18531.

First, some core inconsistencies.

1. Trailing dot.

"Select, move, scale and rotate objects (S)"
"Delete nodes or ways. (...)"

Notice the trailing dot not being there consistently. This inconsistency is present across all the buttons, two more examples - "Open a list of all relations." and "Resolve conflicts".

2. Phrasing differences.

"Open a list of all loaded layers."
"Tags for selected objects."

Notice how these two examples (there are more) are not consistent in their phrasing. To be consistent, one would have to be changed to:
"Open a list of tags for selected objects."
"Loaded layers."

Personally, I'd prefer the shorter version, as the other one is harder to parse, and isn't even correct half of the time, as it _hides/closes_ the layers when they are visible.

3. Inconsistent first letter case.

Most tooltips start with an uppercase letter. Some start with a lowercase one - I believe this might be from core: "configure the map painting style".

Plugin label inconsistencies.

All of the inconsistencies above are observable in various plugins, too.
Perhaps it makes sense to have a three-sentence guideline on these tooltips (start with a capital letter, finish all sentences with a dot, use the short form like this...).
It probably wouldn't be useful to create a separate ticket for each plugin, so I'll just list some examples here:

"List of notes"
"Open Mapillary filter dialog"
"Displays detail information on the currently selected Mapillary image" (notice how this one uses a descriptive verb form, different from most other forms; dropping the verb altogether would also solve this)
"measurement mode"