Remove non-ASCII character

Fix Tencent#824

Author: miloyip

test/unittest/readertest.cpp

@@ -245,13 +245,13 @@ static void TestParseDouble() {
     TEST_DOUBLE(fullPrecision, "0.017976931348623157e+310", 1.7976931348623157e+308); // Max double in another form
 
     // Since
-    // abs((2^-1022 - 2^-1074) - 2.2250738585072012e-308) = 3.109754131239141401123495768877590405345064751974375599... �� 10^-324
-    // abs((2^-1022) - 2.2250738585072012e-308) = 1.830902327173324040642192159804623318305533274168872044... �� 10 ^ -324
+    // abs((2^-1022 - 2^-1074) - 2.2250738585072012e-308) = 3.109754131239141401123495768877590405345064751974375599... x 10^-324
+    // abs((2^-1022) - 2.2250738585072012e-308) = 1.830902327173324040642192159804623318305533274168872044... x 10 ^ -324
     // So 2.2250738585072012e-308 should round to 2^-1022 = 2.2250738585072014e-308
     TEST_DOUBLE(fullPrecision, "2.2250738585072012e-308", 2.2250738585072014e-308); // http://www.exploringbinary.com/java-hangs-when-converting-2-2250738585072012e-308/
 
     // More closer to normal/subnormal boundary
-    // boundary = 2^-1022 - 2^-1075 = 2.225073858507201136057409796709131975934819546351645648... �� 10^-308
+    // boundary = 2^-1022 - 2^-1075 = 2.225073858507201136057409796709131975934819546351645648... x 10^-308
     TEST_DOUBLE(fullPrecision, "2.22507385850720113605740979670913197593481954635164564e-308", 2.2250738585072009e-308);
     TEST_DOUBLE(fullPrecision, "2.22507385850720113605740979670913197593481954635164565e-308", 2.2250738585072014e-308);