Currently

When starting a new post, the first placeholder block has a text label that says Start typing or press (+) to add content.

When you add additional blocks, those text labels say Add text or type / to add content.

Proposal

Considering we don't currently provide slash commands, the second message isn't appropriate in our editor.

I propose that we show 1 consistent message – Start typing or press (+) to add content.

This is related to:
#549