Fix show/hide line numbers in editor

spec/text-editor-registry-spec.js

@@ -425,6 +425,19 @@ describe('TextEditorRegistry', function () {
       expect(editor.hasAtomicSoftTabs()).toBe(true)
     })
 
+    it('enables or disables line numbers based on the config', async function () {
+      editor.update({showLineNumbers: true})
+      expect(editor.showLineNumbers).toBe(true)
+
+      atom.config.set('editor.showLineNumbers', false)
+      registry.maintainConfig(editor)
+      await initialPackageActivation
+      expect(editor.showLineNumbers).toBe(false)
+
+      atom.config.set('editor.showLineNumbers', true)
+      expect(editor.showLineNumbers).toBe(true)
+    })
+
     it('sets the invisibles based on the config', async function () {
       const invisibles1 = {'tab': 'a', 'cr': false, eol: false, space: false}
       const invisibles2 = {'tab': 'b', 'cr': false, eol: false, space: false}

src/text-editor-registry.js

@@ -12,6 +12,7 @@ const EDITOR_PARAMS_BY_SETTING_KEY = [
   ['editor.tabLength', 'tabLength'],
   ['editor.invisibles', 'invisibles'],
   ['editor.showIndentGuide', 'showIndentGuide'],
+  ['editor.showLineNumbers', 'showLineNumbers'],
   ['editor.softWrap', 'softWrapped'],
   ['editor.softWrapHangingIndent', 'softWrapHangingIndentLength'],
   ['editor.softWrapAtPreferredLineLength', 'softWrapAtPreferredLineLength'],