Fix long option format on docs.podman.io

Escape the two dashes, otherwise they are combined into one long dash.
I tested that this change is safe and still renders correctly on github
and with the man pages.

This commit also contains a small change to make it build locally.
Assuming you have the dependencies installed you can do:
```
cd docs
make html
```
Preview the html files in docs/build/html with
`python -m http.server 8000 --directory build/html`.

Fixes containers/podman.io#373

Signed-off-by: Paul Holzinger <paul.holzinger@web.de>

1 files changed, 5 insertions, 5 deletions

diff --git a/docs/source/markdown/podman-volume-inspect.1.md b/docs/source/markdown/podman-volume-inspect.1.md
index ea0ee91b4..7273b817a 100644
--- a/docs/source/markdown/podman-volume-inspect.1.md
+++ b/docs/source/markdown/podman-volume-inspect.1.md
@@ -9,22 +9,22 @@ podman\-volume\-inspect - Get detailed information on one or more volumes
 ## DESCRIPTION
 
 Display detailed information on one or more volumes. The output can be formatted using
-the **--format** flag and a Go template. To get detailed information about all the
-existing volumes, use the **--all** flag.
+the **\-\-format** flag and a Go template. To get detailed information about all the
+existing volumes, use the **\-\-all** flag.
 Volumes can be queried individually by providing their full name or a unique partial name.
 
 
 ## OPTIONS
 
-#### **--all**, **-a**
+#### **\-\-all**, **-a**
 
 Inspect all volumes.
 
-#### **--format**=*format*, **-f**
+#### **\-\-format**=*format*, **-f**
 
 Format volume output using Go template
 
-#### **--help**
+#### **\-\-help**
 
 Print usage statement