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

tldr/termdown

@@ -0,0 +1,29 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# termdown
+
+> Countdown timer and stopwatch for the command-line.
+> More information: <https://github.com/trehn/termdown>.
+
+- Start a stopwatch:
+
+`termdown`
+
+- Start a 1 minute and 30 seconds countdown:
+
+`termdown {{1m30s}}`
+
+- Start a 1 minute 30 seconds countdown with blinking the terminal at the end:
+
+`termdown {{1m30s}} --blink`
+
+- Show a title above countdown:
+
+`termdown {{1m30s}} --title "{{Interesting title}}"`
+
+- Display current time:
+
+`termdown --time`