Properly parse exprsecs in function calls

[sovdeeth]

Problem

Having a section expression in a function call would not properly claim the section, leading to the section never running:

function f(x: worldborder):
    broadcast "%worldborder warning time of {_x}%"

load:
    f(a worldborder):
        set worldborder warning time to 20 ticks

would broadcast 15 seconds, not 1 second.

Solution

Modifies sectioncontext when parsing EffFunctionCall, so the expr sec can properly claim the section.

Testing Completed

Added a regression test.

Supporting Information

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Completes: none
Related: none