Merge branch 'pr-408'

* pr-408:
  bash: update multiline comments examples
  Adding comments section

bash.md

@@ -172,6 +172,20 @@ DIR=${SRC%$BASE}  #=> "/path/to" (dirpath)
 | `${FOO/%from/to}` | Replace suffix |
 | `${FOO/#from/to}` | Replace prefix |
 
+### Comments
+
+```bash
+# Single line comment
+```
+
+```bash
+: '
+This is a
+multi line
+comment
+'
+```
+
 ### Substrings
 
 | `${FOO:0:3}`  | Substring _(position, length)_ |