freeramdisk: add page

[KristopherLeads]

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page(s) have at most 8 examples.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The page(s) follow the style guide.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known):

[KristopherLeads]

Legacy tool from 16796.

Ok, this is a very weird one. So freeramdisk was relatively common on legacy systems like pre-2004ish. I remember it as a low-level utility that you could run to free up your loadin disk especially when using liveboots or ram-loaded distros. Now it's largely deprecated by the system daemons or is handled via specific functions like tmpfs or umount, but as we can see, is still referenced in cheatsheets and textbooks. I think it's worth documenting, but there's also a good argument to be had for not having a tl;dr page for this.

[Managor]

Academic settings might still use legacy tools for a number of reasons. If a tool exists, it's worth documenting as long as the description states that the tool is deprecated.

[Managor]

This should reduce confusion

https://github.com/tldr-pages/tldr/blob/main/contributing-guides/style-guide.md#special-cases

Technical wording on description lines should use the backtick syntax.