Use glamour and termev to render/colorize content (#181)

Merge branch 'master' into use-glamour

select Glamour Theme based on BackgroundColor

Merge branch 'master' into use-glamour

Merge branch 'master' into use-glamour

update termev

update go.mod

label color colorate

use glamour for issue content

Vendor: Add glamour

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: 6543 <6543@obermui.de>
Reviewed-on: https://gitea.com/gitea/tea/pulls/181
Reviewed-by: techknowlogick <techknowlogick@gitea.io>
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>

vendor/github.com/alecthomas/chroma/formatters/tty_truecolour.go

@@ -0,0 +1,42 @@
+package formatters
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/alecthomas/chroma"
+)
+
+// TTY16m is a true-colour terminal formatter.
+var TTY16m = Register("terminal16m", chroma.FormatterFunc(trueColourFormatter))
+
+func trueColourFormatter(w io.Writer, style *chroma.Style, it chroma.Iterator) error {
+	style = clearBackground(style)
+	for token := it(); token != chroma.EOF; token = it() {
+		entry := style.Get(token.Type)
+		if !entry.IsZero() {
+			out := ""
+			if entry.Bold == chroma.Yes {
+				out += "\033[1m"
+			}
+			if entry.Underline == chroma.Yes {
+				out += "\033[4m"
+			}
+			if entry.Italic == chroma.Yes {
+				out += "\033[3m"
+			}
+			if entry.Colour.IsSet() {
+				out += fmt.Sprintf("\033[38;2;%d;%d;%dm", entry.Colour.Red(), entry.Colour.Green(), entry.Colour.Blue())
+			}
+			if entry.Background.IsSet() {
+				out += fmt.Sprintf("\033[48;2;%d;%d;%dm", entry.Background.Red(), entry.Background.Green(), entry.Background.Blue())
+			}
+			fmt.Fprint(w, out)
+		}
+		fmt.Fprint(w, token.Value)
+		if !entry.IsZero() {
+			fmt.Fprint(w, "\033[0m")
+		}
+	}
+	return nil
+}