rpk: fix linter failures.

src/go/rpk/pkg/cli/profile/prompt.go

@@ -84,7 +84,7 @@ Four modifiers are supported, "bold", "faint", "underline", and "invert".
 
 			y, ok := cfg.ActualRpkYaml()
 			if !ok {
-				errmsg = fmt.Sprintf("rpk.yaml file is missing or cannot be loaded")
+				errmsg = "rpk.yaml file is missing or cannot be loaded"
 				return
 			}
 			p := y.Profile(y.CurrentProfile)

src/go/rpk/pkg/cli/topic/describe.go

@@ -385,7 +385,7 @@ func listStartEndOffsets(cl *kgo.Client, topic string, numPartitions int, stable
 
 	// Finally, the HWM.
 	shards = cl.RequestSharded(context.Background(), req)
-	allFailed = kafka.EachShard(req, shards, func(shard kgo.ResponseShard) {
+	kafka.EachShard(req, shards, func(shard kgo.ResponseShard) {
 		resp := shard.Resp.(*kmsg.ListOffsetsResponse)
 		if len(resp.Topics) > 0 {
 			for _, partition := range resp.Topics[0].Partitions {

src/go/rpk/pkg/config/params.go

@@ -829,11 +829,11 @@ func readFile(fs afero.Fs, path string) (string, []byte, error) {
 	return abs, file, err
 }
 
-func (p *Params) backcompatOldCloudYaml(fs afero.Fs) error {
+func (*Params) backcompatOldCloudYaml(fs afero.Fs) error {
 	def, err := DefaultRpkYamlPath()
 	if err != nil {
-		// This error only happens if the user unset $HOME, and if they
-		// do that, we will avoid failing / avoid backcompat here.
+		//nolint:nilerr // This error only happens if the user unset $HOME, and
+		// if they do that, we will avoid failing / avoid backcompat here.
 		return nil
 	}
 
@@ -913,7 +913,7 @@ func (p *Params) readRpkConfig(fs afero.Fs, c *Config) error {
 	if p.ConfigFlag != "" {
 		path = p.ConfigFlag
 	} else if err != nil {
-		// If $HOME is unset, we do not read any file. If the user
+		//nolint:nilerr // If $HOME is unset, we do not read any file. If the user
 		// eventually tries to write, we fail in Write. Allowing
 		// $HOME to not exists allows rpk to work in CI settings
 		// where all config flags are being specified.

src/go/rpk/pkg/config/rpk_yaml.go

@@ -323,4 +323,4 @@ func (d *Duration) UnmarshalText(text []byte) error {
 	return err
 }
 
-func (d *Duration) YamlTypeNameForTest() string { return "duration" }
+func (*Duration) YamlTypeNameForTest() string { return "duration" }