Fix broken synopsis formatting in documentation

Most of the cmd-xxxx.txt pages were still using the legacy 'italics'
asciidoc [1], which caused the synopsis sections to render like this:

'ssh' -p <port> 'gerrit some-command'

Furthermore, the line breaks and indentations were not rendered.

Replaced the legacy 'italics" with _italics_ in all synopsis sections
and changed the block type to [verse]. Verse blocks preserve indents
and line breaks (like <pre> in HTML), but still allow text formatting.

Fixed also some other minor mistakes and formatting errors.

[1] http://asciidoctor.org/docs/migration/#migration-cheatsheet

Change-Id: I457c5e42e3758789f29541d38d6f6c2e25532897
Signed-off-by: Michael Ochmann <michael.ochmann@sap.com>

Documentation/cmd-flush-caches.txt

diff --git a/Documentation/cmd-flush-caches.txt b/Documentation/cmd-flush-caches.txt
index aa9790d..55a201a 100644
--- a/Documentation/cmd-flush-caches.txt
+++ b/Documentation/cmd-flush-caches.txt
@@ -4,10 +4,11 @@
 gerrit flush-caches - Flush some/all server caches from memory
 
 == SYNOPSIS
+[verse]
 --
-'ssh' -p <port> <host> 'gerrit flush-caches' --all
-'ssh' -p <port> <host> 'gerrit flush-caches' --list
-'ssh' -p <port> <host> 'gerrit flush-caches' --cache <NAME> ...
+_ssh_ -p <port> <host> _gerrit flush-caches_ --all
+_ssh_ -p <port> <host> _gerrit flush-caches_ --list
+_ssh_ -p <port> <host> _gerrit flush-caches_ --cache <NAME> ...
 --
 
 == DESCRIPTION