Merge pull request #4430 from Raku/finanalyst-patch-6

document Firefox Unicode config in unicode.rakudoc

Author: finanalyst

doc/Language/unicode.rakudoc

@@ -12,6 +12,12 @@ methods.
 For an overview on MoarVM's internal representation of strings, see the
 L<MoarVM string documentation|https://github.com/MoarVM/MoarVM/blob/master/docs/strings.asciidoc>.
 
+=begin nested
+For security reasons, browsers (eg., Firefox) may restrict the display of Unicode
+glyphs not in a trusted font, even if the OS has a font installed that displays the glyph.
+To overcome this problem for Firefox, set the `privacy.fingerprintingProtection` config option to `False`.
+=end nested
+
 =head1 Filehandles and I/O
 
 X<|Reference,Normalization>