Switch blink.cmp fuzzy to prefer_rust implementation

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lua/plugins/cmp.lua

@@ -15,6 +15,6 @@ require('blink.cmp').setup {
   completion = { documentation = { auto_show = false, auto_show_delay_ms = 500 } },
   sources = { default = { 'lsp', 'path', 'snippets' } },
   snippets = { preset = 'luasnip' },
-  fuzzy = { implementation = 'lua' },
+  fuzzy = { implementation = 'prefer_rust' },
   signature = { enabled = true },
 }