add NEWS entry [ci skip]

Author: KristofferC

NEWS.md

@@ -11,6 +11,12 @@ New language features
     without having to scrub away prompts and outputs.
     This can be disabled or enabled at will with `Base.REPL.enable_promptpaste(::Bool)`.
 
+  * `print_with_color` can now take a color represented by an integer between 0 and 255 inclusive as its first argument.
+    For a number to color mapping please refer to [this chart](https://upload.wikimedia.org/wikipedia/en/1/15/Xterm_256color_chart.svg).
+    It is also possible to use numbers as colors in environment variables that customizes colors in the REPL.
+    For example, to get orange warning messages, simply set `ENV["JULIA_WARN_COLOR"] = 208`.
+    Please note that not all terminals support 256 colors.
+
 Language changes
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