prstat: fix placeholder

[sebastiaanspeck]

• [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 PR title conforms to the recommended templates.

[tldr-bot]

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

pages/sunos/prstat.md:23: TLDR103 Command example is missing its closing backtick
pages.fr/sunos/prstat.md:23: TLDR103 Command example is missing its closing backtick
pages.id/sunos/prstat.md:23: TLDR103 Command example is missing its closing backtick
pages.nl/sunos/prstat.md:23: TLDR103 Command example is missing its closing backtick
pages.pl/sunos/prstat.md:23: TLDR103 Command example is missing its closing backtick
pages.ta/sunos/prstat.md:23: TLDR103 Command example is missing its closing backtick
pages.tr/sunos/prstat.md:23: TLDR103 Command example is missing its closing backtick

Please fix the error(s) and push again.