Add "modernize" linter

Author: dsh2dsh

.golangci.yaml

@@ -10,6 +10,11 @@ formatters:
     - "goimports"
 
   settings:
+    gofumpt:
+      # Choose whether to use the extra rules.
+      # Default: false
+      extra-rules: true
+
     goimports:
       # A list of prefixes, which, if set, checks import paths
       # with the given prefixes are grouped after 3rd-party packages.
@@ -22,10 +27,12 @@ linters:
     - "asciicheck"
     - "bidichk"
     - "copyloopvar"
+    - "embeddedstructfieldcheck"
     - "errorlint"
     - "gocritic"
     - "makezero"
     - "misspell"
+    - "modernize"
     - "nilnesserr"
     - "nolintlint"
     - "perfsprint"
@@ -51,6 +58,10 @@ linters:
         - "(net.Conn).Close"
         - "(*os.File).Close"
 
+      # Display function signature instead of selector.
+      # Default: false
+      verbose: true
+
     nolintlint:
       # Enable to require an explanation of nonzero length after each nolint
       # directive.

cmd/folders.go

@@ -150,7 +150,7 @@ func (self *FoldersCheck) folderError(ctx context.Context, folderId string,
 	} else if len(fileErrors) > 0 {
 		folderError = fileErrors[len(fileErrors)-1]
 	}
-	return
+	return folderError, err
 }
 
 func (self *FoldersCheck) fetchCompletions(ctx context.Context,
@@ -189,13 +189,13 @@ func (self *FoldersCheck) numCompletions() int {
 
 func (self *FoldersCheck) completion(ctx context.Context,
 	folder *api.FolderConfiguration, deviceId string,
-) (comp *api.FolderCompletion, err error) {
-	comp, err = self.client.Completion(ctx, folder.Id, deviceId)
+) (*api.FolderCompletion, error) {
+	comp, err := self.client.Completion(ctx, folder.Id, deviceId)
 	if err != nil {
 		err = fmt.Errorf("completion folder=%q, device=%q: %w",
 			folderName(folder), self.deviceName(deviceId), err)
 	}
-	return
+	return comp, err
 }
 
 func (self *FoldersCheck) deviceName(id string) string {

cmd/seen.go

@@ -170,7 +170,7 @@ func (self *LastSeenCheck) oldest() (deviceId string, seen time.Time) {
 			}
 		}
 	}
-	return
+	return deviceId, seen
 }
 
 func (self *LastSeenCheck) output(deviceId string, lastSeen time.Duration) {