docs: use includes for command help output

docs/commands/new-strategy.md

@@ -0,0 +1,19 @@
+```
+usage: freqtrade new-strategy [-h] [--userdir PATH] [-s NAME]
+                              [--strategy-path PATH]
+                              [--template {full,minimal,advanced}]
+
+options:
+  -h, --help            show this help message and exit
+  --userdir PATH, --user-data-dir PATH
+                        Path to userdata directory.
+  -s NAME, --strategy NAME
+                        Specify strategy class name which will be used by the
+                        bot.
+  --strategy-path PATH  Specify additional strategy lookup path.
+  --template {full,minimal,advanced}
+                        Use a template which is either `minimal`, `full`
+                        (containing multiple sample indicators) or `advanced`.
+                        Default: `full`.
+
+```