Accept more forced color values

Extend the color variables to leniently accept more color values. So
besides only `FORCE_COLOR=256color`, also accept e.g.
`FORCE_COLOR=256colors` to force 256 colors. Similarly, besides
`FORCE_COLOR=truecolor`, accept e.g. `FORCE_COLOR=24bits` to force
true colors.

mordant/src/commonMain/kotlin/com/github/ajalt/mordant/terminal/TerminalDetection.kt

@@ -140,8 +140,8 @@ internal object TerminalDetection {
         else -> when (getEnv("FORCE_COLOR")?.lowercase()) {
             "0", "false", "none" -> NONE
             "1", "", "true", "16color" -> ANSI16
-            "2", "256color" -> ANSI256
-            "3", "truecolor" -> TRUECOLOR
+            "2", in TERM_256COLOR_VALUES -> ANSI256
+            "3", in COLORTERM_TRUECOLOR_VALUES -> TRUECOLOR
             else -> null
         }
     }