ci, co, ident, rcs, rcsdiff, rcsmerge, rlog: add pages

[osmium1]

Adds documentation pages for the RCS (Revision Control System) suite of commands.

Checklist

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• 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 contains at most 5 new pages. (this PR has 7 pages but they're all part of the same toolkit referenced in issue Let's document: rcs #11873)
• The PR is authored by me, or has been human-reviewed if it was created with AI or machine translation software.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known): GNU RCS 5.x
• Reference issue: Let's document: rcs #11873, Reach parity with cheat cheatsheets #3689

[CLAassistant]

All committers have signed the CLA.

[Managor]

Can you make sure that these commands still work with a space before applying them.

[osmium1]

Can you make sure that these commands still work with a space before applying them.

I checked the RCS man pages and the options are documented as directly attached without spaces:

• -r[rev] not -r [rev]
• -m[msg] not -m [msg]

For example, the man page shows: "co -r1.2 example.c"

I want to make sure - should I add the spaces anyway for readability (if RCS accepts both), or keep the documented syntax?

[Managor]

Use a space but only if the command functions with a space. It's part of our Style guide to have a space there for consistency across pages
https://github.com/tldr-pages/tldr/blob/main/contributing-guides/style-guide.md#option-syntax

[osmium1]

The man page shows the syntax as -r[rev] (attached), but I don't have RCS installed to test. If you've verified they work with spaces, I'll apply the suggestions.

[Managor]

I haven't verified it either.

EDIT: I have now.