unamend: fix command summary line
Before this patch, the docstring started with a newline, which led the
summary line (shown in e.g. `hg help -c`) to be blank.
Differential Revision: https://phab.mercurial-scm.org/D1943
test-add.t
test-addremove-similar.t
test-addremove.t
test-ancestor.py
test-automv.t
test-backwards-remove.t
test-bheads.t
test-bisect2.t
test-bookmarks-merge.t
test-bookmarks-strip.t
test-branch-tag-confict.t
test-casecollision.t
test-cat.t
test-changelog-exec.t
test-check-commit.t
test-check-execute.t
test-check-module-imports.t
test-check-pyflakes.t
test-check-pylint.t
test-check-shbang.t
test-children.t
test-commit-unresolved.t
test-completion.t
test-contrib-check-code.t
test-contrib-check-commit.t
test-debugrename.t
test-diff-copy-depth.t
test-diff-hashes.t
test-diff-issue2761.t
test-diff-newlines.t
test-diff-reverse.t
test-diff-subdir.t
test-diffdir.t
test-directaccess.t
test-dirstate-nonnormalset.t
test-doctest.py
test-double-merge.t
test-duplicateoptions.py
test-empty-dir.t
test-empty-file.t
test-empty.t
test-encoding-func.py
test-excessive-merge.t
test-execute-bit.t
test-gpg.t
test-hghave.t
test-imports-checker.t
test-issue1089.t
test-issue1175.t
test-issue1502.t
test-issue1802.t
test-issue1877.t
test-issue1993.t
test-issue522.t
test-issue612.t
test-issue619.t
test-issue672.t
test-issue842.t
test-journal-exists.t
test-locate.t
test-lrucachedict.py
test-manifest.py
test-manifest-merging.t
test-match.py
test-merge-default.t
test-merge-internal-tools-pattern.t
test-merge-remove.t
test-merge-revert.t
test-merge-revert2.t
test-merge-subrepos.t
test-merge10.t
test-merge2.t
test-merge4.t
test-merge5.t
test-merge6.t
test-merge7.t
test-merge8.t
test-mq-qimport-fail-cleanup.t
test-obshistory.t
test-permissions.t
test-push-checkheads-partial-C1.t
test-push-checkheads-partial-C2.t
test-push-checkheads-partial-C3.t
test-push-checkheads-partial-C4.t
test-push-checkheads-pruned-B1.t
test-push-checkheads-pruned-B2.t
test-push-checkheads-pruned-B3.t
test-push-checkheads-pruned-B4.t
test-push-checkheads-pruned-B5.t
test-push-checkheads-pruned-B6.t
test-push-checkheads-pruned-B7.t
test-push-checkheads-pruned-B8.t
test-push-checkheads-superceed-A1.t
test-push-checkheads-superceed-A2.t
test-push-checkheads-superceed-A3.t
test-push-checkheads-superceed-A4.t
test-push-checkheads-superceed-A5.t
test-push-checkheads-superceed-A6.t
test-push-checkheads-superceed-A7.t
test-push-checkheads-superceed-A8.t
test-push-checkheads-unpushed-D1.t
test-push-checkheads-unpushed-D2.t
test-push-checkheads-unpushed-D3.t
test-push-checkheads-unpushed-D4.t
test-push-checkheads-unpushed-D5.t
test-push-checkheads-unpushed-D6.t
test-push-checkheads-unpushed-D7.t
test-record.t
test-rename-dir-merge.t
test-rename-merge1.t
test-rename.t
test-revert-flags.t
test-revert-unknown.t
test-revlog-group-emptyiter.t
test-revlog-mmapindex.t
test-revlog-packentry.t
test-run-tests.py
test-show-stack.t
test-simple-update.t
test-sparse-clear.t
test-sparse-merges.t
test-sparse-requirement.t
test-sparse-verbose-json.t
test-status-terse.t
test-uncommit.t
test-unified-test.t
test-unrelated-pull.t
test-update-issue1456.t
test-update-names.t
test-update-reverse.t
test-xdg.t