feat: add svx icon (#623)

* Update icons_by_file_extension.lua

Added svelte mdvex file extention svx

* Update icons_by_file_extension.lua

Added svx markdown extention

* Fix cterm_color for Svelte Markdown icon

* last changes fix errors using make command

* remove spaces from svx name

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Co-authored-by: Alexander Courtis <alex@courtis.org>

Author: saeedtahmtan

lua/nvim-web-devicons/default/icons_by_file_extension.lua

@@ -411,6 +411,7 @@ return {
   ["svg"]            = { icon = "󰜡", color = "#FFB13B", cterm_color = "214", name = "Svg"                        },
   ["svgz"]           = { icon = "󰜡", color = "#FFB13B", cterm_color = "214", name = "Svgz"                       },
   ["svh"]            = { icon = "󰍛", color = "#019833", cterm_color = "28",  name = "SystemVerilog"              },
+  ["svx"]            = { icon = "", color = "#FF0042", cterm_color = "197", name = "SvelteMarkdown"             },
   ["swift"]          = { icon = "", color = "#E37933", cterm_color = "166", name = "Swift"                      },
   ["t"]              = { icon = "", color = "#519ABA", cterm_color = "74",  name = "Tor"                        },
   ["tbc"]            = { icon = "󰛓", color = "#1E5CB3", cterm_color = "25",  name = "Tcl"                        },