fix(gobd_company): replace literal newline in string with \n escape (CodeRabbit P1)

PR #426's `body_source = "<literal newline>".join(body_lines)` was a
SyntaxError that escaped the smoke test because the smoke test only
exercises uom (the ORM-only path), not l10n_de's data extractor.

CodeRabbit flagged this in the final review at `25e8d2b6` as a
"duplicate" comment carried forward; it remained unresolved through
merge. Fix: `"\n".join(body_lines)` — the intended one-char escape.

Now `python -m ast` parses gobd_company.py cleanly. Smoke test still
passes (no regression).

https://claude.ai/code/session_017gZ6sPRXYPj5n7uJ7NBtRv

Author: claude

tools/odoo-blueprint-extractor/odoo_blueprint_extractor/data_extractors/gobd_company.py

@@ -48,8 +48,7 @@ def _find_compute_method(source: str, method_name: str) -> Optional[Dict]:
             # Extract source lines for body inspection
             lines = source.splitlines()
             body_lines = lines[node.lineno - 1:end]
-            body_source = "
-".join(body_lines)
+            body_source = "\n".join(body_lines)
             return {
                 "name": method_name,
                 "lineno": node.lineno,