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/rosa.go

@@ -37,6 +37,9 @@ func mustDecode(s string) pkg.Checksum {
 	return pkg.MustDecode(s)
 }
 
+// KV is a key-value pair of strings.
+type KV [2]string
+
 var (
 	// AbsUsrSrc is the conventional directory to place source code under.
 	AbsUsrSrc = fhs.AbsUsr.Append("src")
@@ -364,7 +367,7 @@ func (t Toolchain) NewPatchedSource(
 	name, version string,
 	source pkg.Artifact,
 	passthrough bool,
-	patches ...[2]string,
+	patches ...KV,
 ) pkg.Artifact {
 	if passthrough && len(patches) == 0 {
 		return source
@@ -446,7 +449,7 @@ type PackageAttr struct {
 	ScriptEarly string
 
 	// Passed to [Toolchain.NewPatchedSource].
-	Patches [][2]string
+	Patches []KV
 	// Kind of source artifact.
 	SourceKind int