docs: Fixed a few links in manual.md

[vedpawar2254]

Fixed few links and their order, also changed the name to make it little more consistant

let me know if anything else is needed
Thanks

[terriko]

I always appreciate improved links, BUT:

• I think if the desired parameter is a file for both, let's go with SBOM_FILENAME and VEX_FILENAME rather than having either of them be OUTPUT.
• We should change these in the code as well so that the help text matches whatever's in the manual
• Once the code is changed, you'll need to make update the sections where we list arguments (in MANUAL.md and README.md) to match what cve-bin-tool --help actually generates.

But your instinct to at least fix the parameter names is a good one, and can be done now! Let's just make them both FILENAME instead of OUPTUT.