use .. warning:: (#17226)

* remove unnecessary when statement

* remove outdated codes

* use warnings

lib/pure/algorithm.nim

@@ -563,7 +563,8 @@ proc product*[T](x: openArray[seq[T]]): seq[seq[T]] =
   ## Produces the Cartesian product of the array.
   ## Every element of the result is a combination of one element from each seq in `x`,
   ## with the ith element coming from `x[i]`.
-  ## Warning: complexity may explode.
+  ## 
+  ## .. warning:: complexity may explode.
   runnableExamples:
     assert product(@[@[1], @[2]]) == @[@[1, 2]]
     assert product(@[@["A", "K"], @["Q"]]) == @[@["K", "Q"], @["A", "Q"]]

lib/pure/asyncdispatch.nim

@@ -435,7 +435,7 @@ when defined(windows) or defined(nimdoc):
     ## read, or the socket has disconnected in which case the future will
     ## complete with a value of `""`.
     ##
-    ## **Warning**: The `Peek` socket flag is not supported on Windows.
+    ## .. warning:: The `Peek` socket flag is not supported on Windows.
 
 
     # Things to note:
@@ -509,7 +509,7 @@ when defined(windows) or defined(nimdoc):
     ## has disconnected in which case the future will complete with a value of
     ## `0`.
     ##
-    ## **Warning**: The `Peek` socket flag is not supported on Windows.
+    ## .. warning:: The `Peek` socket flag is not supported on Windows.
 
 
     # Things to note:
@@ -572,7 +572,7 @@ when defined(windows) or defined(nimdoc):
     ## Sends `size` bytes from `buf` to `socket`. The returned future
     ## will complete once all data has been sent.
     ##
-    ## **WARNING**: Use it with caution. If `buf` refers to GC'ed object,
+    ## .. warning:: Use it with caution. If `buf` refers to GC'ed object,
     ## you must use GC_ref/GC_unref calls to avoid early freeing of the buffer.
     verifyPresence(socket)
     var retFuture = newFuture[void]("send")

lib/pure/asyncnet.nim

@@ -517,10 +517,9 @@ proc recvLineInto*(socket: AsyncSocket, resString: FutureVar[string],
   ## The `maxLength` parameter determines the maximum amount of characters
   ## that can be read. `resString` will be truncated after that.
   ##
-  ## **Warning**: The `Peek` flag is not yet implemented.
+  ## .. warning:: The `Peek` flag is not yet implemented.
   ##
-  ## **Warning**: `recvLineInto` on unbuffered sockets assumes that the
+  ## .. warning:: `recvLineInto` on unbuffered sockets assumes that the protocol uses `\r\L` to delimit a new line.
-  ## protocol uses `\r\L` to delimit a new line.
   assert SocketFlag.Peek notin flags ## TODO:
   result = newFuture[void]("asyncnet.recvLineInto")
 
@@ -611,10 +610,9 @@ proc recvLine*(socket: AsyncSocket,
   ## The `maxLength` parameter determines the maximum amount of characters
   ## that can be read. The result is truncated after that.
   ##
-  ## **Warning**: The `Peek` flag is not yet implemented.
+  ## .. warning:: The `Peek` flag is not yet implemented.
   ##
-  ## **Warning**: `recvLine` on unbuffered sockets assumes that the protocol
+  ## .. warning:: `recvLine` on unbuffered sockets assumes that the protocol uses `\r\L` to delimit a new line.
-  ## uses `\r\L` to delimit a new line.
   assert SocketFlag.Peek notin flags ## TODO:
 
   # TODO: Optimise this

lib/pure/httpclient.nim

@@ -110,7 +110,7 @@
 ## .. code-block:: Nim
 ##   client.onProgressChanged = nil
 ##
-## **Warning:** The `total` reported by httpclient may be 0 in some cases.
+## .. warning:: The `total` reported by httpclient may be 0 in some cases.
 ##
 ##
 ## SSL/TLS support

lib/system.nim

@@ -1939,8 +1939,7 @@ when notJSnotNims:
       ## With this hook you can influence exception handling on a global level.
       ## If not nil, every 'raise' statement ends up calling this hook.
       ##
-      ## **Warning**: Ordinary application code should never set this hook!
+      ## .. warning:: Ordinary application code should never set this hook! You better know what you do when setting this.
-      ## You better know what you do when setting this.
       ##
       ## If `globalRaiseHook` returns false, the exception is caught and does
       ## not propagate further through the call stack.
@@ -1950,8 +1949,7 @@ when notJSnotNims:
       ## thread local level.
       ## If not nil, every 'raise' statement ends up calling this hook.
       ##
-      ## **Warning**: Ordinary application code should never set this hook!
+      ## .. warning:: Ordinary application code should never set this hook! You better know what you do when setting this.
-      ## You better know what you do when setting this.
       ##
       ## If `localRaiseHook` returns false, the exception
       ## is caught and does not propagate further through the call stack.
@@ -2408,7 +2406,7 @@ when notJSnotNims and hostOS != "standalone":
   proc setCurrentException*(exc: ref Exception) {.inline, benign.} =
     ## Sets the current exception.
     ##
-    ## **Warning**: Only use this if you know what you are doing.
+    ## .. warning:: Only use this if you know what you are doing.
     currException = exc
 elif defined(nimscript):
   proc getCurrentException*(): ref Exception {.compilerRtl.} = discard