feat: Add icon for several KiCad file extensions.

Free software suite for electronic design automation (EDA).

File extensions:
- `.kicad_pro` Project file, containing settings that are shared between the schematic and PCB.
- `.kicad_sch` Schematic files containing all info and the components themselves.
- `.kicad_sym` Schematic symbol library file, containing the component descriptions: graphic shape, pins, fields.
- `.kicad_pcb` Board file containing all info but the page layout.
- `.kicad_mod` Footprint files, containing one footprint description each.
- `.kicad_dru` Design rules file, containing custom design rules for a certain .kicad_pcb file.
- `.kicad_prl` Local settings for the current project; helps Kicad remember the last used settings such as layer visibility or selection filter.
- `.kicad_wks` Page layout (drawing border and title block) description file.

Filenames:
- `sym-lib-table` Symbol library table: list of symbol libraries available in the schematic editor.Board editor files and folders.
- `fp-lib-table` Footprint library table: list of footprint libraries available in the board editor.
- `fp-info-cache` Cache to speed up loading of footprint libraries. Does not need to be distributed with the project or put under version control.

Note: File extensions for legacy file extensions were ignored. Also `.net` and `.cmp` extensions (generic).

src/output/icons.rs

@@ -47,6 +47,7 @@ impl Icons {
     const JSON: char            = '\u{e60b}';  // 
     const KEY: char             = '\u{eb11}';  // 
     const KEYPASS: char         = '\u{f23e}';  // 
+    const KICAD: char           = '\u{f34c}';  // 
     const KRITA: char           = '\u{f33d}';  // 
     const LANG_ASSEMBLY: char   = '\u{e637}';  // 
     const LANG_C: char          = '\u{e61e}';  // 
@@ -245,6 +246,8 @@ const FILENAME_ICONS: Map<&'static str, char> = phf_map! {
     "dune-project"        => Icons::WRENCH,          // 
     "Earthfile"           => '\u{f0ac}',            // 
     "environment"         => Icons::CONFIG,         // 
+    "fp-info-cache"       => Icons::KICAD,          // 
+    "fp-lib-table"        => Icons::KICAD,          // 
     "GNUmakefile"         => Icons::MAKE,           // 
     "go.mod"              => Icons::LANG_GO,        // 
     "go.sum"              => Icons::LANG_GO,        // 
@@ -321,6 +324,7 @@ const FILENAME_ICONS: Map<&'static str, char> = phf_map! {
     "shells"              => Icons::CONFIG,         // 
     "sudoers"             => Icons::LOCK,           // 
     "sxhkdrc"             => Icons::CONFIG,         // 
+    "sym-lib-table"       => Icons::KICAD,          // 
     "system.jwmrc"        => '\u{f35b}',            // 
     "timezone"            => Icons::CLOCK,          // 
     "tsconfig.json"       => Icons::LANG_TYPESCRIPT,// 
@@ -534,6 +538,13 @@ const EXTENSION_ICONS: Map<&'static str, char> = phf_map! {
     "kdenlive"       => '\u{f33c}',              // 
     "kdenlivetitle"  => '\u{f33c}',              // 
     "key"            => Icons::KEY,              // 
+    "kicad_dru"      => Icons::KICAD,            // 
+    "kicad_pcb"      => Icons::KICAD,            // 
+    "kicad_prl"      => Icons::KICAD,            // 
+    "kicad_pro"      => Icons::KICAD,            // 
+    "kicad_sch"      => Icons::KICAD,            // 
+    "kicad_sym"      => Icons::KICAD,            // 
+    "kicad_wks"      => Icons::KICAD,            // 
     "ko"             => Icons::OS_LINUX,         // 
     "kpp"            => Icons::KRITA,            // 
     "kra"            => Icons::KRITA,            // 