removes references to this in the constructor section (#22730)

doc/manual_experimental.md

@@ -2341,11 +2341,10 @@ type Foo* = object
   x: int32
 
 proc makeFoo(x: int32): Foo {.constructor.} =
-  this.x = x
+  result.x = x
 ```
 
 It forward declares the constructor in the type definition. When the constructor has parameters, it also generates a default constructor.
-Notice, inside the body of the constructor one has access to `this` which is of the type `ptr Foo`. No `result` variable is available.
 
 Like `virtual`, `constructor` also supports a syntax that allows to express C++ constraints.
 
@@ -2371,11 +2370,11 @@ type
   NimClass* = object of CppClass
 
 proc makeNimClass(x: int32): NimClass {.constructor:"NimClass('1 #1) : CppClass(0, #1)".} =
-  this.x = x
+  result.x = x
 
 # Optional: define the default constructor explicitly
 proc makeCppClass(): NimClass {.constructor: "NimClass() : CppClass(0, 0)".} =
-  this.x = 1
+  result.x = 1
 ```
 
 In the example above `CppClass` has a deleted default constructor. Notice how by using the constructor syntax, one can call the appropiate constructor.