Docs: Explictly enable JIT in PHP 8.4

[melroy89]

• Enable the opcache.jit option explicitly, before it was implict set to tracing but since PHP 8.4 or above this option will be set to "disable". While JIT was disabled by default in the past as well, you could just enable it by setting "opcache.jit_buffer_size", well that is no more.
• Adding a space before & after the = sign

I use the advance user option:

opcache.jit string|int

    For typical usage, this option accepts one of four string values:

        disable: Completely disabled, cannot be enabled at runtime.
        off: Disabled, but can be enabled at runtime.
        tracing/on: Use tracing JIT. Enabled by default and recommended for most users.
        function: Use function JIT.

    For advanced usage, this option accepts a 4-digit integer CRTO, where the digits mean:

    C (CPU-specific optimization flags)

            0: Disable CPU-specific optimization.
            1: Enable use of AVX, if the CPU supports it.

    R (register allocation)

            0: Don't perform register allocation.
            1: Perform block-local register allocation.
            2: Perform global register allocation.

    T (trigger)

            0: Compile all functions on script load.
            1: Compile functions on first execution.
            2: Profile functions on first request and compile the hottest functions afterwards.
            3: Profile on the fly and compile hot functions.
            4: Currently unused.
            5: Use tracing JIT. Profile on the fly and compile traces for hot code segments.

    O (optimization level)

            0: No JIT.
            1: Minimal JIT (call standard VM handlers).
            2: Inline VM handlers.
            3: Use type inference.
            4: Use call graph.
            5: Optimize whole script.

See also: https://docs.nextcloud.com/server/latest/admin_manual/installation/server_tuning.html

And see also: https://php.watch/versions/8.4/opcache-jit-ini-default-changes