strict effects (#18777)

* fixes #17369
* megatest is green for --cpu:arm64
* docgen output includes more tags/raises
* implemented 'effectsOf' 
* algorithm.nim: uses new effectsOf annotation
* closes #18376
* closes #17475
* closes #13905
* allow effectsOf: [a, b]
* added a test case
* parameters that are not ours cannot be declared as .effectsOf
* documentation
* manual: added the 'sort' example
* bootstrap with the new better options

tests/pragmas/tuserpragma2.nim

@@ -3,9 +3,10 @@ discard """
   file: "tuserpragma2.nim"
   line: 11
 """
-
+{.push warningAsError[Effect]: on.}
 # bug #7216
 {.pragma: my_pragma, raises: [].}
 
 proc test1 {.my_pragma.} =
   raise newException(Exception, "msg")
+{.pop.}