Move pages under tldr, lint run.sh, update docs

tldr/exit

@@ -0,0 +1,17 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# exit
+
+> Exit the shell.
+> More information: <https://manned.org/exit.1posix>.
+
+- Exit with the exit status of the most recently executed command:
+
+`exit`
+
+- Exit with a specific exit status:
+
+`exit {{exit_code}}`