cmatrix: add German translation

[jnmcfly]

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

[tldr-bot]

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

pages.de/common/cmatrix.md:7: TLDR014 Page should contain no trailing whitespace
pages.de/common/cmatrix.md:11: TLDR014 Page should contain no trailing whitespace
pages.de/common/cmatrix.md:15: TLDR014 Page should contain no trailing whitespace
pages.de/common/cmatrix.md:19: TLDR014 Page should contain no trailing whitespace

Please fix the error(s) and push again.

[tldr-bot]

Hello! I've noticed something unusual when checking this PR:

• The page pages.de/common/cmatrix.md has an outdated more info link.

Is this intended? If so, just ignore this comment. Otherwise, please double-check the commits.

[jnmcfly]

Accidentally resolved your comment, will fix asap