vendor: Update everything

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4620

vendor/github.com/chmduquesne/rollinghash/rollinghash.go

@@ -7,11 +7,19 @@ package rollinghash
 
 import "hash"
 
+// DefaultWindowCap is the default capacity of the internal window of a
+// new Hash.
+const DefaultWindowCap = 64
+
+// A Roller is a type that has the method Roll. Roll updates the hash of a
+// rolling window from just the entering byte. You MUST call Write()
+// BEFORE using this method and provide it with an initial window of size
+// at least 1 byte. You can then call this method for every new byte
+// entering the window. The byte leaving the window is automatically
+// computed from a copy of the window internally kept in the checksum.
+// This window is updated along with the internal state of the checksum
+// every time Roll() is called.
 type Roller interface {
-	// Roll updates the hash of a rolling window from the entering byte.
-	// A copy of the window is internally kept from the last Write().
-	// This copy is updated along with the internal state of the checksum
-	// in order to determine the new hash very quickly.
 	Roll(b byte)
 }