cmd/cover: increase coverage precision to at-least 2 decimal places

[staticmukesh]

What version of Go are you using (go version)?

$ go version
go version go1.14.1 darwin/amd64

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

macOS Mojave darwin/amd64

What did you do?

$ go test -v -coverprofile=coverfunc.out ./...
$ go tool cover -func=coverfunc.out
hello.go:84:         Handle                          92.1%
total:              (statements)                     92.1%

What did you expect to see?

I want to see total coverage to be 92.12% instead of 92.1%. We want to track coverage to have higher precision, atleast 2 decimal places.

[gopherbot]

Change https://golang.org/cl/226538 mentions this issue: cover: change coverage precision to .2f