enhancement: Use HEX colors on file icons instead of C256 colors (#4029)

- **PR Description**
Lazygit already accepts to customize UI colors using HEX values but the
color of the icons still were using C256 notation, this PR makes the
change to use HEX values. Not sure if there is a special reason to not
make the change.

You can create the available files with:
```shell
touch _gvimrc _vimrc bin brewfile bspwmrc build build.gradle build.zig.zon cantorrc Cargo.lock Cargo.toml checkhealth cmakelists.txt CODE-OF-CONDUCT.md CODE_OF_CONDUCT CODE_OF_CONDUCT.md COMMIT_EDITMSG commit_editmsg commitlint.config.js commitlint.config.ts compose.yaml compose.yml config containerfile copying copying.lesser docker-compose.yaml docker-compose.yml dockerfile Dockerfile ds_store eslint.config.cjs eslint.config.js eslint.config.mjs eslint.config.ts ext_typoscript_setup.txt favicon.ico fn fp-info-cache fp-lib-table FreeCAD.conf gemfile$ gitignore_global gnumakefile GNUmakefile go.mod go.sum go.work gradle gradle-wrapper.properties gradle.properties gradlew gruntfile.babel.js gruntfile.coffee gruntfile.js gruntfile.ls gruntfile.ts gtkrc gulpfile.babel.js gulpfile.coffee gulpfile.js gulpfile.ls gulpfile.ts hidden hypridle.conf hyprland.conf hyprlock.conf hyprpaper.conf i3blocks.conf i3status.conf include ionic.config.json justfile kalgebrarc kdeglobals kdenlive-layoutsrc kdenliverc kritadisplayrc kritarc lib LICENSE LICENSE.md localized lxde-rc.xml lxqt.conf Makefile mix.lock mpv.conf node_modules npmignore nuxt.config.cjs nuxt.config.js nuxt.config.mjs nuxt.config.ts package-lock.json package.json PKGBUILD platformio.ini pom.xml prettier.config.cjs prettier.config.js prettier.config.mjs prettier.config.ts PrusaSlicer.ini PrusaSlicerGcodeViewer.ini py.typed QtProject.conf R robots.txt rubydoc SECURITY SECURITY.md settings.gradle strings svelte.config.js sxhkdrc sym-lib-table tailwind.config.js tailwind.config.mjs tailwind.config.ts tmux.conf tmux.conf.local tsconfig.json unlicense vagrantfile$ vlcrc webpack weston.ini workspace xmobarrc xmobarrc.hs xmonad.hs xorg.conf xsettingsd.conf yarn.lock 

```
and 
```shell
touch f.{cmake,3gp,3mf,7z,a,aac,ai,aif,aiff,android,ape,apk,app,apple,applescript,asc,ass,astro,avi,avif,avro,awk,azcli,bak,bash,bash_history,bash_pro,bashrc,bat,bats,bazel,bib,bicep,bicepparam,bladephp,blend,blp,bmp,brep,bz,bz2,bz3,bzl,c,c++,cab,cache,cast,cbl,cc,ccm,cfg,cjs,class,clj,cljc,cljd,cljs,cls,cmake,cmd,cob,cobol,coffee,conf,configru,cp,cpio,cpp,cppm,cpy,cr,crdownload,cs,csh,cshtml,cson,csproj,css,csv,csx,cts,cu,cue,cuh,cxx,cxxm,d,dts,dart,db,dconf,deb,desktop,diff,djvu,dll,doc,docx,dot,download,drl,dropbox,ds_store,DS_store,dump,dwg,dxf,ebook,ebuild,editorconfig,edn,eex,ejs,el,elc,elf,elm,eln,env,eot,epp,epub,erb,erl,ex,exe,exs,f#,f3d,f90,fbx,fcbak,fcmacro,fcmat,fcparam,fcscript,fcstd,fcstd1,fctb,fctl,fdmdownload,fish,flac,flc,flf,flv,fnl,font,fs,fsi,fsscript,fsx,gcode,gd,gdoc,gem,gem,gemspec,gform,gif,git,glb,gnumake,go,godot,gql,gradle,graphql,gresource,groovy,gsheet,gslides,guard,gv,gz,h,haml,hbs,hc,heex,hex,hh,hpp,hrl,hs,htm,html,huff,hurl,hx,hxx,ical,icalendar,ico,ics,ifb,ifc,ige,iges,igs,image,img,iml,import,info,ini,ino,ipynb,iso,ixx,j2c,j2k,jad,jar,java,jfi,jfif,jif,jl,jmd,jp2,jpe,jpeg,jpg,jpx,js,json,json5,jsonc,jsx,jwmrc,jxl,kbx,kdb,kdbx,kdenlive,kdenlivetitle,kicad_dru,kicad_mod,kicad_pcb,kicad_prl,kicad_pro,kicad_sch,kicad_sym,kicad_wks,ko,kpp,kra,krz,ksh,kt,kts,latex,lck,leex,less,lff,lhs,license,liquid,localized,lock,log,lrc,lua,luac,luau,lz,lz4,lzh,lzma,lzo,m,m3u,m3u8,m4a,m4v,magnet,make,markdown,material,md,md5,mdx,mint,mjs,mk,mkd,mkv,ml,mli,mm,mo,mobi,mojo,mov,mp3,mp4,mpp,msf,msi,mts,mustache,nfo,nim,nix,node,npmignore,nswag,nu,o,obj,odp,ods,odt,ogg,ogv,opus,org,otf,out,part,patch,pck,pdf,php,pl,pls,ply,pm,png,po,pot,pp,ppt,pptx,prisma,pro,proc,properties,ps1,psb,psd,psd1,psm1,pub,pxd,pxi,pxm,py,pyc,pyd,pyi,pyo,pyw,pyx,qm,qml,qrc,qss,query,r,rake,rake,rar,razor,rb,rdata,rdb,rdoc,rds,readme,res,resi,rlib,rmd,rpm,rproj,rs,rspec,rspec_parallel,rspec_status,rss,rtf,ru,rubydoc,sass,sbt,sc,scad,scala,scm,scss,sh,sha1,sha224,sha256,sha384,sha512,shell,sig,signature,skp,sldasm,sldprt,slim,sln,slvs,sml,so,sol,specjs,specjsx,spects,spectsx,sql,sqlite,sqlite3,srt,ssa,ste,step,stl,stp,strings,sty,styl,stylus,sub,sublime,suo,sv,svelte,svg,svh,swift,t,tar,taz,tbc,tbz,tbz2,tcl,templ,terminal,testjs,testjsx,testts,testtsx,tex,tf,tfvars,tgz,tiff,tlz,tmux,toml,torrent,tres,ts,tscn,tsconfig,tsv,tsx,ttf,twig,txt,txz,typoscript,tz,tzo,ui,v,vala,vh,vhd,vhdl,video,vim,vsh,vsix,vue,war,wasm,wav,webm,webmanifest,webp,webpack,windows,wma,woff,woff2,wrl,wrz,wv,wvc,x,xaml,xcf,xcplayground,xcstrings,xhtml,xls,xlsx,xm,xml,xpi,xul,xz,yaml,yml,zig,zip,zsh,zsh-theme,zshrc,zst,strings}
```
to check the new colors.

Some icons could have be changed because I compared againa
nvim-web-devicons file.

Let me know if you want to change some icon or color.


**Edit**: I added 2 new commits that use glyphs from Nerd Fonts 3.3.0

---

- **Please check if the PR fulfills these requirements**

* [x] Cheatsheets are up-to-date (run `go generate ./...`)
* [X] Code has been formatted (see
[here](https://github.com/jesseduffield/lazygit/blob/master/CONTRIBUTING.md#code-formatting))
* [ ] Tests have been added/updated (see
[here](https://github.com/jesseduffield/lazygit/blob/master/pkg/integration/README.md)
for the integration test guide)
* [x] Text is internationalised (see
[here](https://github.com/jesseduffield/lazygit/blob/master/CONTRIBUTING.md#internationalisation))
* [ ] If a new UserConfig entry was added, make sure it can be
hot-reloaded (see
[here](https://github.com/jesseduffield/lazygit/blob/master/docs/dev/Codebase_Guide.md#using-userconfig))
* [x] Docs have been updated if necessary
* [X] You've read through your own file changes for silly mistakes etc

<!--
Be sure to name your PR with an imperative e.g. 'Add worktrees view'
see https://github.com/jesseduffield/lazygit/releases/tag/v0.40.0 for
examples
-->

pkg/gui/presentation/files.go

@@ -157,7 +157,7 @@ func getFileLine(
 
 	if showFileIcons {
 		icon := icons.IconForFile(name, isSubmodule, isLinkedWorktree, isDirectory)
-		paint := color.C256(icon.Color, false)
+		paint := color.HEX(icon.Color, false)
 		output += paint.Sprint(icon.Icon) + nameColor.Sprint(" ")
 	}
 
@@ -267,7 +267,7 @@ func getCommitFileLine(
 
 	if showFileIcons {
 		icon := icons.IconForFile(name, isSubmodule, isLinkedWorktree, isDirectory)
-		paint := color.C256(icon.Color, false)
+		paint := color.HEX(icon.Color, false)
 		output += paint.Sprint(icon.Icon) + " "
 	}
 

pkg/gui/presentation/icons/icons.go

@@ -8,7 +8,7 @@ import (
 
 type IconProperties struct {
 	Icon  string
-	Color uint8
+	Color string
 }
 
 var isIconEnabled = false