move author name colouring code into its own file

pkg/gui/presentation/commits_test.go

@@ -1,20 +0,0 @@
-package presentation
-
-import "testing"
-
-func TestGetInitials(t *testing.T) {
-	for input, expectedOutput := range map[string]string{
-		"Jesse Duffield":     "JD",
-		"Jesse Duffield Man": "JD",
-		"JesseDuffield":      "Je",
-		"J":                  "J",
-		"六书六書":               "六",
-		"書":                  "書",
-		"":                   "",
-	} {
-		output := getInitials(input)
-		if output != expectedOutput {
-			t.Errorf("Expected %s to be %s", output, expectedOutput)
-		}
-	}
-}