Add names and sizes for all attachments except images, and (as with
arbitrary attachments), clicking on the text will open a save dialog.
In the absence of a filename, choose something that makes sense.
Display different icons for different media types, including distinct icons
for voice notes and audio files.
In iOS theme, audio, video, voice, and files are all encapsulated in bubbles.
Closes#804Closes#842Closes#836
// FREEBIE
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