When Fetching Node & Yarn, show the tool name as well

[charlespierce]

Currently, when we fetch Node or Yarn, the Progress Bar shows:

Fetching v10.15.3 [======>

This can be confusing as it's sometimes shown when you run an unrelated command (the autofetching). We should include the name of the tool we are fetching. Also, related to #373, we should show the version in the typical Node ecosystem formatting of tool@version:

Fetching [email protected] [======>