Fixes from melpa review

Author: ericdallo

README.md

@@ -52,7 +52,7 @@ Besides the `lsp-mode` features, `lsp-dart` implements the [custom methods featu
 * `lsp-dart-only-analyze-projects-with-open-files` - analysis will only be performed for projects that have open files rather than the root workspace folder.
 * `lsp-dart-suggest-from-unimported-libraries` - completion will not include symbols that are not already imported into the current file.
 * `lsp-dart-closing-labels` - Enable the closing labels feature on server lsp.
-* `lsp-dart-closing-labels-prefix` - The prefix string to be concatened with the closing label.
+* `lsp-dart-closing-labels-prefix` - The prefix string to be concatenated with the closing label.
 * `lsp-dart-closing-labels-size` - The font size factor to be multiplied by the closing labels font size.
 * `lsp-dart-outline` - Enable the outline tree view feature on server lsp.
 * `lsp-dart-flutter-outline` - Enable the Flutter outline tree view feature on server lsp.

lsp-dart.el

@@ -42,7 +42,7 @@ When nil, it will try to find the dart sdk from the dart or flutter executables
 in the PATH env."
   :group 'lsp-dart
   :risky t
-  :type 'directory)
+  :type '(choice directory nil))
 
 (defcustom lsp-dart-server-command nil
   "The analysis_server executable to use."
@@ -71,7 +71,7 @@ be sent with information to render editor closing labels."
   :group 'lsp-dart)
 
 (defcustom lsp-dart-closing-labels-prefix " "
-  "The prefix string to be concatened with the closing label."
+  "The prefix string to be concatenated with the closing label."
   :type 'string
   :group 'lsp-dart)