Add command to find pull request for a commit

[bk2204]

Oftentimes, users wish to know which pull request introduced a commit. We should add a technique which works for at least GitHub, GitLab, and Bitbucket that finds the closest pull request that introduces a commit.

[Dustin4444]

Oftentimes, users wish to know which pull request introduced a commit. We should add a technique which works for at least GitHub, GitLab, and Bitbucket that finds the closest pull request that introduces a commit.

[LemmingAvalanche]

For Bitbucket I do

• git when-merged --log <commit> (link)
  • might need --recursive if the project likes complex merge histories
• Take the PR number from the commit message

[Dustin4444]

Pull