Fix Git editor reword workflow and UI coverage

- show Git editor file paths instead of the submitted git command
- surface follow-up commit message editors during interactive rebase reword
- add rename-commit UI tests for editor and amend-message solution paths
- add broader embedded level solution scenarios for alternate Git workflows

app/src/main/java/solutions/tretter/githugandroid/levels/PullLevel.kt

@@ -40,5 +40,6 @@ internal fun pullLevel(): Level = level(
     testCases = listOf(
         levelTestCase("pull explicit remote branch", "git pull origin master"),
         levelTestCase("pull default origin", "git pull"),
+        levelTestCase("fetch then merge", "git fetch origin", "git merge origin/master"),
     ),
 )