gh-148327: Update syntax error example in tutorial

[blesson-07]

gh-148327: Update syntax error example in tutorial

Closes #148327

Replace the outdated syntax error example with a clearer one.
Update the syntax error example from while True print('Hello world') to a[1]] = 0, which gives a clearer unmatched ']' error and better shows arrow placement.

[python-cla-bot]

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[StanFromIreland]

CC @erlend-aasland, per #30097 (comment)

[sharktide]

Looks good to me, left one wording suggestion. Up to you if you want to take it :)

[sharktide]

Suggested change

	at the earliest point in the line where the error was detected.
	at the earliest point in the line in which the error was detected.

[Andrew5057]

"Where" seemed fine to me, but that's purely opinion.

[Andrew5057]

I think I'm actually -1 here.

First, what makes the example outdated? I get the following:

>>> while True print('Hello world')
  File "<python-input-0>", line 1
    while True print('Hello world')
               ^^^^^
SyntaxError: invalid syntax

that closely matches what the documentation currently has:

>>> while True print('Hello world')
  File "<stdin>", line 1
    while True print('Hello world')
               ^^^^^
SyntaxError: invalid syntax

So I'm not sure what the "outdated" here refers to. The "python-input-0" is maybe worth changing, but I don't think the while-loop stuff is.

Second, I think the old example is clearer than the new one. The tutorial contains this paragraph:

The parser repeats the offending line and displays little arrows pointing at the place where the error was detected. Note that this is not always the place that needs to be fixed. In the example, the error is detected at the function print(), since a colon (':') is missing just before it.

The original while loop example is a deliberate choice to show the misleading arrow placement; it's useful to see that the arrows are at print() even though the problem is before that. This new example loses that nuance since the arrow shows you exactly what you're supposed to fix.