add more minor 3.7 new features (#2000)

part of #1965

stdlib/2and3/hmac.pyi

@@ -35,3 +35,6 @@ def compare_digest(a: str, b: str) -> bool: ...
 def compare_digest(a: bytes, b: bytes) -> bool: ...
 @overload
 def compare_digest(a: bytearray, b: bytearray) -> bool: ...
+
+if sys.version_info >= (3, 7):
+    def digest(key: _B, msg: _B, digest: str) -> bytes: ...

stdlib/2and3/locale.pyi

@@ -94,8 +94,12 @@ def strcoll(string1: _str, string2: _str) -> int: ...
 def strxfrm(string: _str) -> _str: ...
 def format(format: _str, val: Union[float, Decimal], grouping: bool = ...,
            monetary: bool = ...) -> _str: ...
-def format_string(format: _str, val: Sequence[Any],
-                  grouping: bool = ...) -> _str: ...
+if sys.version_info >= (3, 7):
+    def format_string(format: _str, val: Sequence[Any],
+                      grouping: bool = ..., monetary: bool = ...) -> _str: ...
+else:
+    def format_string(format: _str, val: Sequence[Any],
+                      grouping: bool = ...) -> _str: ...
 def currency(val: int, symbol: bool = ..., grouping: bool = ...,
              international: bool = ...) -> _str: ...
 if sys.version_info >= (3, 5):

stdlib/2and3/math.pyi

@@ -61,6 +61,8 @@ if sys.version_info >= (3, 3):
 def modf(x: float) -> Tuple[float, float]: ...
 def pow(x: float, y: float) -> float: ...
 def radians(x: float) -> float: ...
+if sys.version_info >= (3, 7):
+    def remainder(x: float, y: float) -> float: ...
 def sin(x: float) -> float: ...
 def sinh(x: float) -> float: ...
 def sqrt(x: float) -> float: ...