🖊️ Improved error message for missing colons in level 17

[boryanagoncharenko]

• Add preprocessing rules which take an argument in order to allow for a rule to turn into an error without copying the old rule definition. For example, error_ifelse<old_rule_to_error ifelse> is used in level 8 to transform the old flat if-else to an error.
• Add errors for if-else statements, loops and function definitions missing a colon in level 17

Fixes #5222

How to test

• Automated tests are added for the new preprocessing functionality and for the commands missing colons in level 17.
• To see the error message, run the following program in level 17 and try removing any of the colons at a time. The message should direct you to the right line.

define function with b:
    i = 1
    while i < b:
        print i
        i = i + 1

b = 10
if b is 1:
    call function with b
elif b is 2:
    call function with b
else:
    call function with b

if b is pressed:
    call function with b
elif c is pressed:
    call function with b
else:
    call function with b

[jpelay]

Excellent! I love the new grammar merger file.

[jpelay]

I really like this!

[mergify]

Thank you for contributing! Your pull request is now going on the merge train (choo choo! Do not click update from main anymore, and be sure to allow changes to be pushed to your fork).

[mergify]

Thank you for contributing! Your pull request is now going on the merge train (choo choo! Do not click update from main anymore, and be sure to allow changes to be pushed to your fork).