Markdown code blocks part 5 (#20236)

No logic was added, just a few more `*.md` files have been migrated.

doc/manual.md

@@ -5083,10 +5083,7 @@ exception tracking.
 
 There is also a way which can be used to forbid certain effects:
 
-.. code-block:: nim
-    :test: "nim c --warningAsError:Effect:on $1"
-    :status: 1
-
+  ```nim  test = "nim c --warningAsError:Effect:on $1"  status = 1
   type IO = object ## input/output effect
   proc readLine(): string {.tags: [IO].} = discard
   proc echoLine(): void = discard
@@ -5096,13 +5093,14 @@ There is also a way which can be used to forbid certain effects:
     echoLine()
     # the compiler prevents this:
     let y = readLine()
+  ```
 
 The `forbids` pragma defines a list of illegal effects - if any statement
 invokes any of those effects, the compilation will fail.
 Procedure types with any disallowed effect are the subtypes of equal
 procedure types without such lists:
 
-.. code-block:: nim
+  ```nim
   type MyEffect = object
   type ProcType1 = proc (i: int): void {.forbids: [MyEffect].}
   type ProcType2 = proc (i: int): void
@@ -5123,6 +5121,7 @@ procedure types without such lists:
   ## these are OK because ProcType2 doesn't have any effect requirement:
   caller2(toBeCalled1)
   caller2(toBeCalled2)
+  ```
 
 `ProcType2` is a subtype of `ProcType1`. Unlike with tags, the parent context - the function which calls other functions with forbidden effects - doesn't inherit the forbidden list of effects.
 
@@ -8079,18 +8078,20 @@ from C. The optional argument is a string containing the C identifier. If
 the argument is missing, the C name is the Nim identifier *exactly as
 spelled*:
 
-.. code-block::
+  ```nim
   proc printf(formatstr: cstring) {.header: "<stdio.h>", importc: "printf", varargs.}
+  ```
 
 When `importc` is applied to a `let` statement it can omit its value which
 will then be expected to come from C. This can be used to import a C `const`:c:\:
 
-.. code-block::
+  ```nim
   {.emit: "const int cconst = 42;".}
 
   let cconst {.importc, nodecl.}: cint
 
   assert cconst == 42
+  ```
 
 Note that this pragma has been abused in the past to also work in the
 JS backend for JS objects and functions. Other backends do provide