message: change spacing on BranchName
diff: ```.jsx
  <BranchName>a_new_feature_branch</BranchName>
  +
  <ExampleHeading mt={3}>BranchName with Octicon</ExampleHeading>
  <BranchName>
  <Octicon icon={GitBranch} />
  a_new_feature_branch
  </BranchName>
  +
  <ExampleHeading mt={3}>Linked BranchName</ExampleHeading>
  <BranchName is="a" href="/">
  a_new_feature_branch
  