Fix typo and edit for clarity in the docstrings of sys.float_info. (GH-2251)

Objects/floatobject.c

-
 /* Float object implementation */
 
 /* XXX There should be overflow checks here, but it's hard to check
@@ -54,7 +53,7 @@ static PyStructSequence_Field floatinfo_fields[] = {
                     "is representable"},
     {"max_10_exp",      "DBL_MAX_10_EXP -- maximum int e such that 10**e "
                     "is representable"},
-    {"min",             "DBL_MIN -- Minimum positive normalizer float"},
+    {"min",             "DBL_MIN -- Minimum positive normalized float"},
     {"min_exp",         "DBL_MIN_EXP -- minimum int e such that radix**(e-1) "
                     "is a normalized float"},
     {"min_10_exp",      "DBL_MIN_10_EXP -- minimum int e such that 10**e is "
@@ -64,7 +63,7 @@ static PyStructSequence_Field floatinfo_fields[] = {
     {"epsilon",         "DBL_EPSILON -- Difference between 1 and the next "
                     "representable float"},
     {"radix",           "FLT_RADIX -- radix of exponent"},
-    {"rounds",          "FLT_ROUNDS -- addition rounds"},
+    {"rounds",          "FLT_ROUNDS -- rounding mode"},
     {0}
 };