PR made against beta branch since the PR it is fixing is not yet part of a stable release.
Cc @feerrenrut

Link to issue number:

None
Fix-up of #9843.

Summary of the issue:

When using api.copyToClip with new argument notify=True, if any call to the clipboard API fails, "Unable to copy" message should be reported since the merge of #9843. This is however not the case.
It was discovered during my computer stress tests (for unrelated reasons). The stress tests consists in keeping NVDA+T pressed during a long time (30 seconds or one minute) in MS Word.
After a while, the clipboard is overflowed by API operations and become inaccessible. The following error is reported in the log:

IO - inputCore.executeGesture (11:15:19.230) - winInputHook (11196):
Input: kb(desktop):NVDA+t
ERROR - scriptHandler.executeScript (11:15:19.190) - MainThread (13740):
error executing script: <bound method GlobalCommands.script_title of <globalCommands.GlobalCommands object at 0x06ADD6F0>> with gesture 'NVDA+t'
Traceback (most recent call last):
File "api.pyc", line 317, in copyToClip
File "contextlib.pyc", line 112, in __enter__
File "winUser.pyc", line 758, in openClipboard
PermissionError: [WinError 5] Accès refusé.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "scriptHandler.pyc", line 208, in executeScript
File "globalCommands.pyc", line 1689, in script_title
File "api.pyc", line 321, in copyToClip
TypeError: catching classes that do not inherit from BaseException is not allowed

As per #9843, "Unable to copy" should be reported in this case and no error should occur.

Description of how this pull request fixes the issue:

In api.copyToClip, caught OSError instead of unappropriated ctypes.WinError which is a function.

I have seen in NVDA code (probably Python 2 legacy code) that we use WinError in this case.
Anyway, Python doc tells us to use OSError:

ctypes.WinError(code=None, descr=None)
Windows only: this function is probably the worst-named thing in ctypes. It creates an instance of OSError. If code is not specified, GetLastError is called to determine the error code. If descr is not specified, FormatError() is called to get a textual description of the error.
Changed in version 3.3: An instance of WindowsError used to be created.

In any case, WinError and OSError are the same.

Testing performed:

Tested with the same stress test that the failing copy is reported. Since many messages are reported and interrupted, I have heard only the beginning of the message that differs from the message reporting a successful copy. I have then checked this message in the log.

Known issues with pull request:

None

Change log entry:

Not needed since #9843 is not yet part of a stable release.

Cc @JulienCochuyt (author of #9843).