Fix links in git-absorb.txt

They are rendering inline as `[GIT_SEQUENCE_EDITOR][]` etc., with
a block below that supplies the mapping. Unsightly.

Author: blairconrad

Documentation/git-absorb.txt

@@ -102,18 +102,14 @@ SHA of the commit it should be squashed into.
 
 3. If you are satisfied with the output, `git rebase -i --autosquash` to
 squash the `fixup!` commits into their predecessors. You can set the
-[GIT_SEQUENCE_EDITOR][] environment variable if you don't need to edit
-the rebase TODO file.
+https://stackoverflow.com/a/29094904[GIT_SEQUENCE_EDITOR] environment
+variable if you don't need to edit the rebase TODO file.
 
 4. If you are not satisfied (or if something bad happened), `git reset
 --soft` to the pre-absorption commit to recover your old state. (You can
-find the commit in question with `git reflog`.) And if you think `git
-absorb` is at fault, please [file an issue][].
-
-.............................................................................
-[GIT_SEQUENCE_EDITOR]: https://stackoverflow.com/a/29094904
-[file an issue]: https://github.com/tummychow/git-absorb/issues/new
-.............................................................................
+find the commit in question with `git reflog`.) And if you think
+`git absorb` is at fault, please
+https://github.com/tummychow/git-absorb/issues/new[file an issue].
 
 CONFIGURATION
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