deprecate unsafeAddr; extend addr (#19373)

* deprecate unsafeAddr; extend addr

addr is now available for all addressable locations, unsafeAddr is deprecated and become an alias for addr

* follow @Vindaar's advice

* change the signature of addr

* unsafeAddr => addr (stdlib)

* Update changelog.md

* unsafeAddr => addr (tests)

* Revert "unsafeAddr => addr (stdlib)"

This reverts commit ab83c99c507048a8396e636bf22d55fdd84d7d1c.

* doc changes; thanks to @konsumlamm

Co-authored-by: konsumlamm <44230978+konsumlamm@users.noreply.github.com>

Co-authored-by: konsumlamm <44230978+konsumlamm@users.noreply.github.com>

doc/manual.rst

@@ -3502,8 +3502,9 @@ location is `T`, the `addr` operator result is of the type `ptr T`. An
 address is always an untraced reference. Taking the address of an object that
 resides on the stack is **unsafe**, as the pointer may live longer than the
 object on the stack and can thus reference a non-existing object. One can get
-the address of variables, but one can't use it on variables declared through
-`let` statements:
+the address of variables. For easier interoperability with other compiled languages
+such as C, retrieving the address of a `let` variable, a parameter,
+or a `for` loop variable can be accomplished too:
 
 .. code-block:: nim
 
@@ -3515,24 +3516,18 @@ the address of variables, but one can't use it on variables declared through
   # --> ref 0x7fff6b71b670 --> 0x10bb81050"Hello"
   echo cast[ptr string](t3)[]
   # --> Hello
-  # The following line doesn't compile:
+  # The following line also works
   echo repr(addr(t1))
-  # Error: expression has no address
-
 
 The unsafeAddr operator
 -----------------------
 
-For easier interoperability with other compiled languages such as C, retrieving
-the address of a `let` variable, a parameter, or a `for` loop variable can
-be accomplished by using the `unsafeAddr` operation:
+The `unsafeAddr` operator is a deprecated alias for the `addr` operator:
 
 .. code-block:: nim
-
   let myArray = [1, 2, 3]
   foreignProcThatTakesAnAddr(unsafeAddr myArray)
 
-
 Procedures
 ==========
 

doc/manual_experimental.rst

@@ -603,7 +603,7 @@ has `source` as the owner. A path expression `e` is defined recursively:
 - Object field access `e.field` is a path expression.
 - `system.toOpenArray(e, ...)` is a path expression.
 - Pointer dereference `e[]` is a path expression.
-- An address `addr e`, `unsafeAddr e` is a path expression.
+- An address `addr e` is a path expression.
 - A type conversion `T(e)` is a path expression.
 - A cast expression `cast[T](e)` is a path expression.
 - `f(e, ...)` is a path expression if `f`'s return type is a view type.