Fix some typos

lib/help.js

@@ -216,7 +216,7 @@ class Help {
 
   /**
    * Get the subcommand summary to show in the list of subcommands.
-   * (Fallback to description for backwards compatiblity.)
+   * (Fallback to description for backwards compatibility.)
    *
    * @param {Command} cmd
    * @returns {string}

tests/deprecated.test.js

@@ -21,7 +21,7 @@ describe('option with regular expression instead of custom processing function',
     expect(program.opts().cheese).toEqual('tasty');
   });
 
-  test('when argument does mot matches regexp then value is default', () => {
+  test('when argument does not match regexp then value is default', () => {
     const program = new commander.Command();
     program
       .option('--cheese <type>', 'cheese type', /mild|tasty/, 'mild');

tests/help.wrap.test.js

@@ -142,7 +142,7 @@ Commands:
     expect(program.helpInformation()).toBe(expectedOutput);
   });
 
-  test('when option descripton preformatted then only add small indent', () => {
+  test('when option description preformatted then only add small indent', () => {
     // #396: leave custom format alone, apart from space-space indent
     const optionSpec = '-t, --time <HH:MM>';
     const program = new commander.Command();