message: Update app-custom-theme.md
  added missing coma in the pageTheme header color list.
diff: @@ -128,7 +128,7 @@ const themeOptions = createThemeOptions({
  tool: genPageTheme(['#123456','#123456'], shapes.round),
  service: genPageTheme(['#123456','#123456'], shapes.wave),
  website: genPageTheme(['#123456','#123456'], shapes.wave),
  - library: genPageTheme(['#123456','#123456'] shapes.wave),
  + library: genPageTheme(['#123456','#123456'], shapes.wave),
  other: genPageTheme(['#123456','#123456'], shapes.wave),
  app: genPageTheme(['#123456','#123456'], shapes.wave),
  apis: genPageTheme(['#123456','#123456'], shapes.wave),
  