Add rounded borders to LSP/Diagnostics float windows

lua/plugins/completions.lua

@@ -118,10 +118,34 @@ return {
         { name = 'path' },
         -- { name = 'cmdline' },
       },
+
+      window = {
+        completion = cmp.config.window.bordered(),
+        documentation = cmp.config.window.bordered(),
+      },
     })
 
-    -- Disable displaying diagnostics as virtual text
-    vim.diagnostic.config({ virtual_text = false })
+    -- Customise LSP UI
+    vim.lsp.handlers['textDocument/hover'] = vim.lsp.with(
+      vim.lsp.handlers.hover, {
+        border = 'rounded',
+        title = 'Hover',
+      }
+    )
+    vim.lsp.handlers["textDocument/signatureHelp"] = vim.lsp.with(
+      vim.lsp.handlers.signature_help, {
+        border = 'rounded',
+        title = 'Signature Help'
+      }
+    )
+
+    -- Customise diagnostics UI
+    vim.diagnostic.config({
+      float = {
+        border = 'rounded', -- Enable rounded border on floats
+      },
+      virtual_text = false, -- Disable trailing virtual text
+    })
 
     -- Diagnostic mappings
     -- TODO: trouble.nvim mappings instead? https://youtu.be/MuUrCcvE-Yw?t=631