https://www.khronos.org/registry/vulkan/specs/1.0/apispec.html#_vksampleraddressmode_3
I don't see it here
https://javadoc.lwjgl.org/org/lwjgl/vulkan/VK10.html
From the VkSamplerCreateInfo javadoc:
QuoteSAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE indicates that the mirror clamp to edge wrap mode will be used. This is only valid if the VK_KHR_mirror_clamp_to_edge extension is enabled.
You will find VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE in KHRSamplerMirrorClampToEdge. You must explicitly enable the VK_KHR_sampler_mirror_clamp_to_edge extension to use it.
Also, a tip: The LWJGL javadoc is generated using jdk9, which adds search functionality. You can visit https://javadoc.lwjgl.org/ and use the search field to find the API you're looking for.