Minor issues with: sarif-sdk/docs /multitool-usage.md file

[davewichers]

This file currently begins with the following:

: Install the current Sarif.Multitool to the local machine cache (requires Node.js)
npm i -g @microsoft/sarif-multitool

: Run the Sarif.Multitool using the NPM-installed copy
npx @microsoft/sarif-multitool <args>

: See Usage
Sarif.Multitool @microsoft/sarif-multitool help

: Convert a Fortify file to SARIF
Sarif.Multitool convert Current.fpr -tool FortifyFpr -output Current.sarif

1. The last line shown above has a bug, because the parameters need to have TWO - in front of them, not one. i.e., --tool and --output

2. Also, the 2nd block says you run Sarif.Multitool using the command: npx @microsoft/sarif-multitool <args>, and yet all the examples below that line use simply: Sarif.Multitool <args>, which I don't believe works.

Shouldn't all the examples below show the commands as: npx @microsoft/sarif-multitool <args>, not Sarif.Multitool <args>