internal/rosa: key-value type

This type is used very frequently. The new type is much easier to type and can receive helper methods eventually if needed.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/meson.go

@@ -59,7 +59,7 @@ type MesonHelper struct {
 	Script string
 
 	// Flags passed to the setup command.
-	Setup [][2]string
+	Setup []KV
 	// Whether to skip meson test.
 	SkipTest bool
 }
@@ -113,7 +113,7 @@ meson test \
 cd "$(mktemp -d)"
 meson setup \
 	` + strings.Join(slices.Collect(func(yield func(string) bool) {
-		for _, v := range append([][2]string{
+		for _, v := range append([]KV{
 			{"prefix", "/system"},
 			{"buildtype", "release"},
 		}, attr.Setup...) {