Removed handling of trailing spaces from lexKey since it belongs to lexBeforeValue

lex.go

diff --git a/lex.go b/lex.go
index 09312ce..62cdb9d 100644
--- a/lex.go
+++ b/lex.go
@@ -250,10 +250,6 @@
 		l.emit(itemKey)
 	}
 
-	// ignore trailing spaces
-	l.acceptRun(whitespace)
-	l.ignore()
-
 	return lexBeforeValue
 }