[bug] Gazelle fails to parse go.mod if godebug is set #2137
Description
go.mod accepts godebug as per https://go.dev/doc/modules/gomod-ref#godebug, but gazelle fails when this field is set.
repro: https://github.com/albertocavalcante/repros/tree/main/2025-07-08-bazel-gazelle
stacktrace:
ERROR: /private/var/tmp/_bazel_user/b657a3728cd030fff5d5deff34f01ea1/external/gazelle+/internal/bzlmod/go_mod.bzl:215:21: Traceback (most recent call last):
File "/private/var/tmp/_bazel_user/b657a3728cd030fff5d5deff34f01ea1/external/gazelle+/internal/bzlmod/go_deps.bzl", line 428, column 95, in *go*deps_impl
module_path, module_tags_from_go_mod, go_mod_replace_map, tools = deps_from_go_mod(module_ctx, from_file_tag.go_mod)
File "/private/var/tmp/_bazel_user/b657a3728cd030fff5d5deff34f01ea1/external/gazelle+/internal/bzlmod/go_mod.bzl", line 171, column 26, in deps_from_go_mod
go_mod = parse_go_mod(go_mod_content, go_mod_path)
File "/private/var/tmp/_bazel_user/b657a3728cd030fff5d5deff34f01ea1/external/gazelle+/internal/bzlmod/go_mod.bzl", line 215, column 21, in parse_go_mod
fail("{}:{}: unexpected token '{}' at start of line".format(path, line_no, tokens[0]))
Error in fail: /Users/user/dev/workspace/repros/2025-07-08-bazel-gazelle/go.mod:5: unexpected token 'godebug' at start of line