just be explicit about match checking

fun.go

@@ -27,7 +27,6 @@ import (
 	"regexp"
 	"strings"
 	"time"
-	"unicode"
 
 	"golang.org/x/net/html"
 	"humungus.tedunangst.com/r/webs/cache"
@@ -458,7 +457,6 @@ func memetize(honk *Honk) {
 	honk.Noise = re_memes.ReplaceAllStringFunc(honk.Noise, repl)
 }
 
-// be mindful not to match trailing @
 var re_quickmention = regexp.MustCompile("(^|[ \n])@[[:alnum:]]+([ \n.,']|$)")
 
 func quickrename(s string, userid int64) string {
@@ -474,7 +472,8 @@ func quickrename(s string, userid int64) string {
 			prefix += "@"
 			m = m[1:]
 			tail := ""
-			if last := m[len(m)-1]; last == ' ' || last == '\n' || unicode.IsPunct(rune(last)) {
+			if last := m[len(m)-1]; last == ' ' || last == '\n' ||
+				last == '.' || last == ',' || last == '\'' {
 				tail = m[len(m)-1:]
 				m = m[:len(m)-1]
 			}