nmap: add page

[TerribleCodes]

• 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 PR title conforms to the recommended templates.
• Version of the command being documented: Nmap 7.92
  Let's document: pen-testing tools #6863

[tldr-bot]

The build for this PR failed with the following error(s):

pages/common/nmap.md:
Error: Parse error on line 17:
...r}} {{{ip_address}}` `- Service Scanni
-----------------------^
Expecting 'NEWLINE', 'TEXT', 'DASH', 'BACKTICK', got 'COMMAND_TEXT'
pages/common/nmap.md:5: TLDR016 Label for information link should be spelled exactly `More information: `
pages/common/nmap.md:11: TLDR104 Example descriptions should prefer infinitive tense (e.g. write) over present (e.g. writes) or gerund (e.g. writing)
pages/common/nmap.md:16: TLDR103 Command example is missing its closing backtick

Please fix the error(s) and push again.