fix #488 - support user field for completion

- a few other backends use `user` instead of `username` or `login`
  (e.g. gopass-jsonapi, keepass2csv importer, fpm2 importer)
- shorter to type when extracting field separately (e.g. CLI/clipboard) tools

passKitTests/Models/PasswordTest.swift

@@ -32,6 +32,7 @@ class PasswordTest: XCTestCase {
             XCTAssertEqual(password.numberOfUnknowns, 0)
 
             XCTAssertNil(password.username)
+            XCTAssertNil(password.user)
             XCTAssertNil(password.urlString)
             XCTAssertNil(password.login)
 
@@ -53,7 +54,7 @@ class PasswordTest: XCTestCase {
     }
 
     func testSimplePasswordFile() {
-        let additions = SECURE_URL_FIELD | LOGIN_FIELD | USERNAME_FIELD | NOTE_FIELD
+        let additions = SECURE_URL_FIELD | LOGIN_FIELD | USERNAME_FIELD | USER_FIELD | NOTE_FIELD
         let fileContent = PASSWORD_STRING | additions
         let password = getPasswordObjectWith(content: fileContent)
 
@@ -62,11 +63,13 @@ class PasswordTest: XCTestCase {
         XCTAssert(SECURE_URL_FIELD ∈ password)
         XCTAssert(LOGIN_FIELD ∉ password)
         XCTAssert(USERNAME_FIELD ∉ password)
+        XCTAssert(USER_FIELD ∉ password)
         XCTAssert(NOTE_FIELD ∈ password)
 
         XCTAssertEqual(password.urlString, SECURE_URL_FIELD.content)
         XCTAssertEqual(password.login, LOGIN_FIELD.content)
         XCTAssertEqual(password.username, USERNAME_FIELD.content)
+        XCTAssertEqual(password.user, USER_FIELD.content)
     }
 
     func testTwoPasswords() {

passKitTests/Testbase/TestBase.swift

@@ -22,6 +22,7 @@ let SECURE_URL_FIELD = "url" => "https://secure.com"
 let INSECURE_URL_FIELD = "url" => "http://insecure.com"
 let LOGIN_FIELD = "login" => "login name"
 let USERNAME_FIELD = "username" => "微 分 方 程"
+let USER_FIELD = "user" => "积 分 方 程"
 let NOTE_FIELD = "note" => "A NOTE"
 let HINT_FIELD = "some hints" => "äöüß // €³ %% −° && @²` | [{\\}],.<>"
 let TOTP_URL_FIELD = "otpauth" => "//totp/email@email.com?secret=abcd1234"