Documentation: render dash correctly

Three hyphens are rendered verbatim in documentation, so "--" has to be
used to produce a dash.  Fix asciidoc output for dashes.  This is
similar to previous commits f0b922473e (Documentation: render special
characters correctly, 2021-07-29) and de82095a95 (doc
hash-function-transition: fix asciidoc output, 2021-02-05).

Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-apply.txt

@@ -208,7 +208,7 @@ behavior:
 * `warn` outputs warnings for a few such errors, but applies the
   patch as-is (default).
 * `fix` outputs warnings for a few such errors, and applies the
-  patch after fixing them (`strip` is a synonym --- the tool
+  patch after fixing them (`strip` is a synonym -- the tool
   used to consider only trailing whitespace characters as errors, and the
   fix involved 'stripping' them, but modern Gits do more).
 * `error` outputs warnings for a few such errors, and refuses

Documentation/git-read-tree.txt

@@ -219,7 +219,7 @@ see which of the "local changes" that you made were carried forward by running
 `git diff-index --cached $M`.  Note that this does not
 necessarily match what `git diff-index --cached $H` would have
 produced before such a two tree merge.  This is because of cases
-18 and 19 --- if you already had the changes in $M (e.g. maybe
+18 and 19 -- if you already had the changes in $M (e.g. maybe
 you picked it up via e-mail in a patch form), `git diff-index
 --cached $H` would have told you about the change before this
 merge, but it would not show in `git diff-index --cached $M`

Documentation/git.txt

@@ -619,7 +619,7 @@ The file parameters can point at the user's working file
 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 when a new file is added), or a temporary file (e.g. `old-file` in the
 index).  `GIT_EXTERNAL_DIFF` should not worry about unlinking the
-temporary file --- it is removed when `GIT_EXTERNAL_DIFF` exits.
+temporary file -- it is removed when `GIT_EXTERNAL_DIFF` exits.
 +
 For a path that is unmerged, `GIT_EXTERNAL_DIFF` is called with 1
 parameter, <path>.

Documentation/gitformat-signature.txt

@@ -37,7 +37,7 @@ line.
 This is even true for an originally empty line.  In the following
 examples, the end of line that ends with a whitespace letter is
 highlighted with a `$` sign; if you are trying to recreate these
-example by hand, do not cut and paste them---they are there
+example by hand, do not cut and paste them--they are there
 primarily to highlight extra whitespace at the end of some lines.
 
 The signed payload and the way the signature is embedded depends

Documentation/technical/hash-function-transition.txt

@@ -562,7 +562,7 @@ hash re-encode during clone and to encourage peers to modernize.
 The design described here allows fetches by SHA-1 clients of a
 personal SHA-256 repository because it's not much more difficult than
 allowing pushes from that repository. This support needs to be guarded
-by a configuration option --- servers like git.kernel.org that serve a
+by a configuration option -- servers like git.kernel.org that serve a
 large number of clients would not be expected to bear that cost.
 
 Meaning of signatures

Documentation/technical/rerere.txt

@@ -99,7 +99,7 @@ conflict to leave line D means that the user declares:
     compatible with what AB and AC wanted to do.
 
 So the conflict we would see when merging AB into ACAB should be
-resolved the same way---it is the resolution that is in line with that
+resolved the same way--it is the resolution that is in line with that
 declaration.
 
 Imagine that similarly previously a branch XYXZ was forked from XY,