Add Allocator_Error return to core:container/priority_queue procedures

[mororo18]

Some procedures in core:container/priority_queue, such as init, may fail due to allocation errors but currently do not return any error information. This proposal suggests updating such procedures to return runtime.Allocator_Error to properly propagate allocation failures.

Example:

// Current
init :: proc(pq: ^$Q/Priority_Queue($T), less: proc(a, b: $T) -> bool, swap: proc(q: []$T, i, j: int), capacity: int = DEFAULT_CAPACITY, allocator := context.allocator) {…}

// Proposed
init :: proc(pq: ^$Q/Priority_Queue($T), less: proc(a, b: $T) -> bool, swap: proc(q: []$T, i, j: int), capacity: int = DEFAULT_CAPACITY, allocator := context.allocator) -> (runtime.Allocator_Error) #optional_allocator_error {…}

[Kelimion]

Good idea. Turned it into an Issue @ #5048.

[Kelimion]

Implemented in PR #5050.