git-rebase.txt: fix description list separator

We don't give a "::" for the list separator, but just a single ":". This
ends up rendering literally, "--apply: Use applying strategies ...". As
a follow-on error, the list continuation, "+", also ends up rendering
literally (because we don't have a list).

This was introduced in 52eb738 ("rebase: add an --am option",
2020-02-15) and survived the rename in 10cdb9f ("rebase: rename the
two primary rebase backends", 2020-02-15).

Signed-off-by: Martin Ågren <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: Martin Ågren

Documentation/git-rebase.txt

@@ -258,7 +258,7 @@ See also INCOMPATIBLE OPTIONS below.
 	original branch. The index and working tree are also left
 	unchanged as a result.
 
---apply:
+--apply::
 	Use applying strategies to rebase (calling `git-am`
 	internally).  This option may become a no-op in the future
 	once the merge backend handles everything the apply one does.