Fixed Incorrect Links
Corrected the links in the following two files as requested:
- File node/BUILDING.md:
- [Enabling FIPS using Node.js options](#enabling-fips-using-node.js-options)
+ [Enabling FIPS using Node.js options](#enabling-fips-using-nodejs-options)
and
- File node/doc/api/net.md:
- [`'error'`]: #event-error_1
+ [`'error'`]: #event-error-1