update comment

inst/tests/tests.Rraw

@@ -20598,7 +20598,7 @@ test(2295.3, is.data.table(d2))
 # #6588: .checkTypos used to give arbitrary strings to stopf as the first argument
 test(2296, d2[x %no such operator% 1], error = '%no such operator%')
 
-# coerce Dates to double if join on multiple columns, #6602
+# fix coercing integer/double for joins on multiple columns, #6602
 x = data.table(a=1L)
 y = data.table(c=1L, d=1)
 test(2297.01, y[x, on=.(c == a, d == a), verbose=TRUE], data.table(c=1L, d=1L), output="Coercing .*a to type double.*Coercing .*c to type double")