[CodeMirror] Incremental parse bug

[microbit-matt-hillsdon]

Delete/replace the colon after the last if True in the while. Notice the structural highlighting is broken for the last if/else.

Edit the last if/else and it fixes itself.

Needs minimising and a CodeMirror bug reporting (once we've checked we're on the latest).

# Add your Python code here. E.g.
from microbit import *


while True:
    display.scroll('Hello, World!')
    display.show(Image.HEART)
    sleep(2000)
    if True:
        pass
    if True:
        pass

if True:
    pass
    
if True:
    pass
else:
    pass

[microbit-matt-hillsdon]

Minimized:

if True:
    if True:
        pass

if True:
    pass
else:
    pass

edit the second colon.

[microbit-matt-hillsdon]

Raised codemirror/dev#509

[microbit-matt-hillsdon]

CM bug is fixed (unclear by what change, but doesn't reproduce with the latest deps).

Next step is to upgrade CM and test.

[microbit-matt-hillsdon]

Closed by #232.

[microbit-matt-hillsdon]

Reopening as we've had to revert the CodeMirror upgrade due to #243.

[microbit-matt-hillsdon]

We re-upgraded. Closing.