doc: replace "--" with {litdd} in credential-cache/fsmonitor

Asciidoc renders `--` as em-dash.  This is not appropriate for command
names.  It also breaks linkgit links to these commands.

Fix git-credential-cache--daemon and git-fsmonitor--daemon.  The latter
was added 3248486920 (fsmonitor: document builtin fsmonitor, 2022-03-25)
and included several links.  A check for broken links in the HTML docs
turned this up.

Manually inspecting the other Documentation/git-*--*.txt files turned up
the issue in git-credential-cache--daemon.

While here, quote `git credential-cache--daemon` in the synopsis to
match the vast majority of our other documentation.

Signed-off-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config/core.txt

@@ -63,7 +63,7 @@ core.protectNTFS::
 
 core.fsmonitor::
 	If set to true, enable the built-in file system monitor
-	daemon for this working directory (linkgit:git-fsmonitor--daemon[1]).
+	daemon for this working directory (linkgit:git-fsmonitor{litdd}daemon[1]).
 +
 Like hook-based file system monitors, the built-in file system monitor
 can speed up Git commands that need to refresh the Git index

Documentation/git-credential-cache--daemon.txt

@@ -1,5 +1,5 @@
-git-credential-cache--daemon(1)
-===============================
+git-credential-cache{litdd}daemon(1)
+====================================
 
 NAME
 ----
@@ -8,7 +8,7 @@ git-credential-cache--daemon - Temporarily store user credentials in memory
 SYNOPSIS
 --------
 [verse]
-git credential-cache--daemon [--debug] <socket>
+'git credential-cache{litdd}daemon' [--debug] <socket>
 
 DESCRIPTION
 -----------

Documentation/git-fsmonitor--daemon.txt

@@ -1,5 +1,5 @@
-git-fsmonitor--daemon(1)
-========================
+git-fsmonitor{litdd}daemon(1)
+=============================
 
 NAME
 ----
@@ -8,10 +8,10 @@ git-fsmonitor--daemon - A Built-in File System Monitor
 SYNOPSIS
 --------
 [verse]
-'git fsmonitor--daemon' start
-'git fsmonitor--daemon' run
-'git fsmonitor--daemon' stop
-'git fsmonitor--daemon' status
+'git fsmonitor{litdd}daemon' start
+'git fsmonitor{litdd}daemon' run
+'git fsmonitor{litdd}daemon' stop
+'git fsmonitor{litdd}daemon' status
 
 DESCRIPTION
 -----------

Documentation/git-update-index.txt

@@ -528,7 +528,7 @@ This feature is intended to speed up git operations for repos that have
 large working directories.
 
 It enables git to work together with a file system monitor (see
-linkgit:git-fsmonitor--daemon[1]
+linkgit:git-fsmonitor{litdd}daemon[1]
 and the
 "fsmonitor-watchman" section of linkgit:githooks[5]) that can
 inform it as to what files have been modified. This enables git to avoid