For SerenityOS, we parse emoji metadata from the UCD to learn emoji
groups, subgroups, names, etc. We used this information only in the
emoji picker dialog. It is entirely unused within Ladybird.
This removes our dependence on the UCD emoji file, as we no longer
need any of its information. All we need to know is the file path to
our custom emoji, which we get from Meta/emoji-file-list.txt.
This was preventing some unqualified emoji sequences from rendering
properly, such as the custom SerenityOS flag. We rendered the flag
correctly when given the fully qualified sequence:
U+1F3F3 U+FEOF U+200D U+1F41E
But were not detecting the unqualified sequence as an emoji when also
filtering for emoji-presentation sequences:
U+1F3F3 U+200D U+1F41E
This adds an option to only detect emoji that should always present as
emoji. For example, the copyright symbol (unless followed by an emoji
presentation selector) should render as text.
According to TR #51, the "best definition of the full set [of emojis] is
in the emoji-test.txt file". This defines not only the emoji themselves,
but the order in which they should be displayed, and what "group" of
emojis they belong to.
