Autocomplete for custom options not triggered until after first option is completed

[inkOrCloud]

Description

When using buf with custom options in vscode-buf, autocomplete does not trigger for the first custom option. Autocomplete only starts working after the first option is fully written, and then it correctly suggests completions for subsequent options.

Example

message RegisterRequest {
  string email = 1;
  string password = 2 [
    (buf.validate.field).string.min_len = 1,   // No autocomplete triggered here
    (buf.validate.field).string.max_len = 20,  // Autocomplete works here
  ];
  string code = 3;
}

• At (buf.validate.field).string.min_len = 1, autocomplete does not trigger.
• After completing the first option, autocomplete works for (buf.validate.field).string.max_len = 20 and subsequent options.

Environment

• VSCode: 1.106.10
• buf-cli: 1.60.0
• System: Linux kernel 6.17.8-arch1-1
• vscode-buf extension: 0.8.1

Expected Behavior

Autocomplete should trigger immediately when starting to type a custom option, not only after the first option is fully completed.

Actual Behavior

Autocomplete only triggers after the first custom option is finished, making the initial option harder to write without manual reference.