doc: fix TOML otel exporter example — multi-line inline table is invalid

[448523760]

What is the type of issue?

Documentation is incorrect

What is the issue?

The otel exporter example in docs/config.md is misleading and will cause
the configuration parser to fail if copied verbatim.

Summary

The example uses a TOML inline table but spreads the inline-table braces
across multiple lines. TOML inline tables must be contained on a single line
(key = { a = 1, b = 2 }); placing newlines inside the braces triggers a
parse error in most TOML parsers and prevents Codex from starting.

Reproduction

1. Paste the snippet below into ~/.codex/config.toml (or your project config).
2. Run codex (or the command that loads the config).
3. The process will fail to start with a TOML parse error similar to:

Error loading config.toml: TOML parse error at line 55, column 27
   |
55 | exporter = { otlp-http = {
   |                           ^
newlines are unsupported in inline tables, expected nothing

Problematic snippet (as currently shown in the docs)

[otel]
exporter = { otlp-http = {
  endpoint = "https://otel.example.com/v1/logs",
  protocol = "binary",
  headers = { "x-otlp-api-key" = "${OTLP_TOKEN}" }
}}

Recommended fixes

[otel.exporter."otlp-http"]
endpoint = "https://otel.example.com/v1/logs"
protocol = "binary"

[otel.exporter."otlp-http".headers]
"x-otlp-api-key" = "${OTLP_TOKEN}"

Or, keep an inline table but write it on one line (valid but less readable):

[otel]
exporter = { "otlp-http" = { endpoint = "https://otel.example.com/v1/logs", protocol = "binary", headers = { "x-otlp-api-key" = "${OTLP_TOKEN}" } } }

---

This will avoid confusing users who copy/paste the example and then see a
parse error at startup.

Where did you find it?

• https://github.com/openai/codex/blob/main/docs/config.md#otel
• https://github.com/openai/codex/blob/main/docs/example-config.md#example-configtoml