Better diagnostics highlighting for Dracula theme. (helix-editor#5236)

Author: Chirikumbrah

runtime/themes/dracula.toml

@@ -55,6 +55,9 @@
 "markup.quote" = { fg = "yellow", modifiers = ["italic"] }
 "markup.raw" = { fg = "foreground" }
 
+"diagnostic".underline = { color = "orange", style = "curl" }
+"diagnostic.error".underline = { color = "red", style = "curl" }
+
 [palette]
 background = "#282a36"
 background_dark = "#21222c"