t/lib-rebase: improve documentation of set_fake_editor()

Firstly, make it reflect better what actually happens. Not omitting some
possibilities makes it easier to fully exploit them, and not
contradicting the implementation makes it easier to grok and thus modify
the code.

Secondly, improve the overall structure, putting more general info
further up.

Thirdly, document `merge`, `fakesha`, and `break`, which were previously
omitted entirely.

Signed-off-by: Oswald Buddenhagen <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ossilator

t/lib-rebase.sh

@@ -8,18 +8,21 @@
 # - check that non-commit messages have a certain line count with $EXPECT_COUNT
 # - check the commit count in the commit message header with $EXPECT_HEADER_COUNT
 # - rewrite a rebase -i script as directed by $FAKE_LINES.
-#   $FAKE_LINES consists of a sequence of words separated by spaces.
-#   The following word combinations are possible:
+#   $FAKE_LINES consists of a sequence of words separated by spaces;
+#   spaces inside the words are encoded as underscores.
+#   The following words are possible:
 #
-#   "<lineno>" -- add a "pick" line with the SHA1 taken from the
-#       specified line.
+#   "<cmd>" -- override the command for the next line specification. Can be
+#       "pick", "squash", "fixup[_-(c|C)]", "edit", "reword", "drop",
+#       "merge[_-(c|C)_<rev>]", or "bad" for an invalid command.
 #
-#   "<cmd> <lineno>" -- add a line with the specified command
-#       ("pick", "squash", "fixup"|"fixup_-C"|"fixup_-c", "edit", "reword" or "drop")
-#       and the SHA1 taken from the specified line.
+#   "<lineno>" -- add a command, using the specified line as a template.
+#       If the command has not been overridden, the line will be copied
+#       verbatim, usually resulting in a "pick" line.
 #
-#   "_" -- add a space, like "fixup_-C" implies "fixup -C" and
-#       "exec_cmd_with_args" add an "exec cmd with args" line.
+#   "fakesha" -- add a command ("pick" by default), using a fake SHA1.
+#
+#   "exec_[command...]", "break" -- add the specified command.
 #
 #   "#" -- Add a comment line.
 #