doc: fix lint warning in doc/api/esm.md
https://github.com/nodejs/node/pull/31479 landed on master with the following warning from the markdown linter: https://github.com/nodejs/node/runs/531048109?check_suite_focus=true#step:4:6
doc/api/esm.md
920:84 warning Line must be at most 80 characters maximum-line-length remark-lint
Refs: https://github.com/nodejs/node/pull/31479
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
documentation is changed or added -
commit message follows commit guidelines