Use lexical-binding for themes

Use lexical-binding for themes

* etc/themes/adwaita-theme.el:
* etc/themes/deeper-blue-theme.el:
* etc/themes/dichromacy-theme.el:
* etc/themes/light-blue-theme.el:
* etc/themes/manoj-dark-theme.el:
* etc/themes/misterioso-theme.el:
* etc/themes/tango-dark-theme.el:
* etc/themes/tango-theme.el:
* etc/themes/tsdh-dark-theme.el:
* etc/themes/tsdh-light-theme.el:
* etc/themes/wheatgrass-theme.el:
* etc/themes/whiteboard-theme.el:
* etc/themes/wombat-theme.el: Use lexical-binding.