Feature Request: Some ALLEGRO symbols are not included in doc search

[MarkOates]

From time to time I find myself looking for symbols such as ALLEGRO_DEPTH_TEST, ALLEGRO_FULLSCREEN_WINDOW, but they don't exist in the search.

The file that currently contains the searchable keywords (search_index.js) only includes doc listings but not arbitrary symbols that might be shown under the entry for that listing, for example the flags in al_set_new_display_flags.