This commit changes the following icon definitions to use
more specific emoji as icons. All of the new definitions are
padded with spaces to ensure they use two cells each.

ICON_CHESS "" -> "♟️ " (chess notation)
ICON_FSHARP "" -> "🔷" (blue diamond looks like F Sharp logo)
ICON_FONT "" -> "🔤" (letters abc)
ICON_HTML "" -> "🌍" (globe)
ICON_JAVASCRIPT "" -> ICON_SCRIPT (use a less generic emoji)
ICON_MS_EXCEL ICON_WORDDOC -> "📗" (green book for Excel)
ICON_MUSIC "🎧" (headphones and notes for music folder)
ICON_MUSICFILE ICON_MUSIC -> "🎵" (one musical note for a song)
ICON_PLAYLIST "" -> "🎶" (multiple notes for a playlist)
ICON_PHOTOSHOP ICON_PICTUREFILE -> "🖌️ " (paintbrush symbolising photo editing)
ICON_PICTUREFILE ICON_PICTURES -> "🖼️ " (a framed picture)
ICON_RUST "" -> "🦀" (crab emoji looks like Rust mascot)
ICON_SASS "" -> ICON_EXT_CSS (CSS preprocessor)
ICON_VIDEOFILE ICON_VIDEOS -> "🎞 " (a film strip to symbolise a video)
ICON_VIDEOS "🎞 " -> "🎬" (a clapper board for videos folder)
ICON_VIM "" -> "🪛" (the power tool for everyone)
ICON_EXT_COFFEE "" -> ICON_JAVASCRIPT (JS preprocessor)
ICON_EXT_DEB ICON_LINUX -> "🍥" (Debian swirl)
ICON_EXT_GO "" -> "💨" (Go logo dashing away)
ICON_EXT_MAT "" -> ICON_EXT_M (MATLAB)
ICON_EXT_NIX "" -> "❄️ " (Nix language logo like snowflake)
ICON_EXT_PHP "🌐" -> ICON_HTML (use same Emoji for PHP and HTML)
ICON_EXT_ROM "" -> "🔒" (a padlock)
ICON_EXT_TS "" -> ICON_JAVASCRIPT (JS with static typing)