Update map.sh

[rmdhfz]

This pull request optimizes and fixes the bash script by making the following changes:

• Replaced #!/bin/sh with #!/bin/bash to ensure that the script uses bash instead of sh.
• Renamed the findURL function to find_url to conform to the standard naming convention in bash.
• Used double quotes instead of single quotes in the find_url function to allow variable expansion.
• Used sed instead of cut to extract the lesson name from the article filename in the find_url function.
• Used cd instead of pushd and popd to change directories.
• Used while read -r instead of echo "$mapping" | while read to avoid a subshell and potential issues with whitespace in the input.
• Replaced sed "s/[0-9]* //" with cut -d' ' -f2- to extract the title from the mapping input.

[gopherbot]

Message from Gopher Robot:

Patch Set 1:

Congratulations on opening your first change. Thank you for your contribution!

Next steps: A maintainer will review your change and provide feedback. See https://go.dev/doc/contribute#review for more info and tips to get your patch through code review.

Most changes in the Go project go through a few rounds of revision. This can be surprising to people new to the project. The careful, iterative review process is our way of helping mentor contributors and ensuring that their contributions have a lasting impact.

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/490075. After addressing review feedback, remember to publish your drafts!