Fix various typos in doc (#1134)

docs/DafnyRef/Statements.md

@@ -450,14 +450,14 @@ A RHS with a method call cannot be mixed with a RHS containing multiple expressi
 For example, the desugaring of
 ```dafny
 method m(Status r) returns (rr: Status) {
-  var j, k;
-  j, k :- r, 7;
+  var k;
+  k :- r, 7;
   ...
 }
 ```
 is
 ```dafny
-var j, k;
+var k;
 var tmp;
 tmp, k := r, 7;
 if tmp.IsFailure() {
@@ -1010,10 +1010,10 @@ method Sum(x: Tree) returns (r: int)
 {
   match x {
     case Empty => r := 0;
-	case Node(t1, d, t2) =>
-	  var v1 := Sum(t1);
-	  var v2 := Sum(t2);
-	  r := v1 + d + v2;
+    case Node(t1, d, t2) =>
+      var v1 := Sum(t1);
+      var v2 := Sum(t2);
+      r := v1 + d + v2;
   }
 }
 ```

docs/QuickReference.md

@@ -83,7 +83,7 @@ This can be made clearer in the program text by declaring the method with `lemma
 
 Here is an example method that takes 3 integers as in-parameters and returns these in 3 out-parameters in sorted order:
 ```
-method Sort(a: int b: int, c: int) returns (x: int, y: int, z: int)
+method Sort(a: int, b: int, c: int) returns (x: int, y: int, z: int)
   ensures x <= y <= z && multiset{a, b, c} == multiset{x, y, z}
 {
   x, y, z := a, b, c;
@@ -324,7 +324,7 @@ Finally, to make a sequence from some elements, enclose them in square brackets.
 For example, `[x,y]` is the sequence consisting of the two elements `x` and `y` such that `[x,y][0] == x` and `[x,y][1] == y`, `[x]` is the singleton sequence whose only element is `x`, and `[]` is the empty sequence.
 
 
-The if-then-else expression has the form: `if BoolExpr then Expr0 else Else1`
+The if-then-else expression has the form: `if BoolExpr then Expr0 else Expr1`
 
 where Expr0 and Expr1 are any expressions of the same type.
 Unlike the if statement, the if-then-else expression uses the `then` keyword, and must include an explicit `else` branch.