PCRE2 search does not support \u{0061} in regex

[mjbvz]

Issue Type: Bug

Testing #61744

Repo

1. Enable pcre2 search
2. Open search and enable regular expression search
3. Search for \u{0061} (a)

Bug
No search results.

If you disable pcre2 search and search then you get the expected results. \x{0061} does work with PCRE2

VS Code version: Code - Insiders 1.29.0-insider (d7ac6e8, 2018-11-01T06:11:43.390Z)
OS version: Darwin x64 18.0.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-4770HQ CPU @ 2.20GHz (8 x 2200)
GPU Status	2d_canvas: enabled checker_imaging: disabled_off flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: enabled rasterization: enabled video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled
Load (avg)	4, 3, 3
Memory (System)	16.00GB (0.05GB free)
Process Argv	-psn_0_52474376
Screen Reader	no
VM	22%

[roblourens]

I remap \u1234 to \x1234 but not \u{1234} because it isn't supported by JS correctly yet.

> /\u{0061}/.test(Array(62).join('u'))
true

[roblourens]

Also see #61746

[roblourens]

Requires #61746