make the stdlib work with the changed docgen

lib/pure/collections/critbits.nim

@@ -205,7 +205,7 @@ proc `[]`*[T](c: var CritBitTree[T], key: string): var T {.inline,
 proc mget*[T](c: var CritBitTree[T], key: string): var T {.inline, deprecated.} =
   ## retrieves the value at ``c[key]``. The value can be modified.
   ## If `key` is not in `t`, the ``KeyError`` exception is raised.
-  ## Use ```[]``` instead.
+  ## Use ``[]`` instead.
   get(c, key)
 
 iterator leaves[T](n: Node[T]): Node[T] =

lib/pure/collections/sets.nim

@@ -195,7 +195,7 @@ proc mget*[A](s: var HashSet[A], key: A): var A {.deprecated.} =
   ## returns the element that is actually stored in 's' which has the same
   ## value as 'key' or raises the ``KeyError`` exception. This is useful
   ## when one overloaded 'hash' and '==' but still needs reference semantics
-  ## for sharing. Use ```[]``` instead.
+  ## for sharing. Use ``[]`` instead.
   s[key]
 
 proc contains*[A](s: HashSet[A], key: A): bool =

lib/pure/streams.nim

@@ -271,7 +271,7 @@ proc peekStr*(s: Stream, length: int): TaintedString =
 proc readLine*(s: Stream, line: var TaintedString): bool =
   ## reads a line of text from the stream `s` into `line`. `line` must not be
   ## ``nil``! May throw an IO exception.
-  ## A line of text may be delimited by ```LF`` or ``CRLF``.
+  ## A line of text may be delimited by ``LF`` or ``CRLF``.
   ## The newline character(s) are not part of the returned string.
   ## Returns ``false`` if the end of the file has been reached, ``true``
   ## otherwise. If ``false`` is returned `line` contains no new data.