fix #782 (bring vendor into the main tree)

vendor/github.com/goshuirc/irc-go/ircfmt/doc.go

@@ -0,0 +1,86 @@
+// written by Daniel Oaks <daniel@danieloaks.net>
+// released under the ISC license
+
+/*
+Package ircfmt handles IRC formatting codes, escaping and unescaping.
+
+This allows for a simpler representation of strings that contain colour codes,
+bold codes, and such, without having to write and handle raw bytes when
+assembling outgoing messages.
+
+This lets you turn raw IRC messages into our escaped versions, and turn escaped
+versions back into raw messages suitable for sending on IRC connections. This
+is designed to be used on things like PRIVMSG / NOTICE commands, MOTD blocks,
+and such.
+
+The escape character we use in this library is the dollar sign ("$"), along
+with the given escape characters:
+
+	--------------------------------
+	 Name           | Escape | Raw
+	--------------------------------
+	 Dollarsign     |   $$   |  $
+	 Bold           |   $b   | 0x02
+	 Colour         |   $c   | 0x03
+	 Monospace      |   $m   | 0x11
+	 Reverse Colour |   $v   | 0x16
+	 Italic         |   $i   | 0x1d
+	 Strikethrough  |   $s   | 0x1e
+	 Underscore     |   $u   | 0x1f
+	 Reset          |   $r   | 0x0f
+	--------------------------------
+
+Colours are escaped in a slightly different way, using the actual names of them
+rather than just the raw numbers.
+
+In our escaped format, the colours for the fore and background are contained in
+square brackets after the colour ("$c") escape. For example:
+
+	Red foreground:
+		Escaped:  This is a $c[red]cool message!
+		Raw:      This is a 0x034cool message!
+
+	Blue foreground, green background:
+		Escaped:  This is a $c[blue,green]rad message!
+		Raw:      This is a 0x032,3rad message!
+
+When assembling a raw message, we make sure to use the full colour code
+("02" vs just "2") when it could become confused due to numbers just after the
+colour escape code. For instance, lines like this will be unescaped correctly:
+
+	No number after colour escape:
+		Escaped:  This is a $c[red]cool message!
+		Raw:      This is a 0x034cool message!
+
+	Number after colour escape:
+		Escaped:  This is $c[blue]20% cooler!
+		Raw:      This is 0x030220% cooler
+
+Here are the colour names and codes we recognise:
+
+	--------------------
+	 Code | Name
+	--------------------
+	  00  | white
+	  01  | black
+	  02  | blue
+	  03  | green
+	  04  | red
+	  05  | brown
+	  06  | magenta
+	  07  | orange
+	  08  | yellow
+	  09  | light green
+	  10  | cyan
+	  11  | light cyan
+	  12  | light blue
+	  13  | pink
+	  14  | grey
+	  15  | light grey
+	  99  | default
+	--------------------
+
+These other colours aren't given names:
+https://modern.ircdocs.horse/formatting.html#colors-16-98
+*/
+package ircfmt