Add docs for the strip commands

_filters/lstrip.md

@@ -1,3 +1,9 @@
 ---
 title: lstrip
 ---
+
+Strips all whitespace (tabs, spaces, and newlines) from the left side of a string.
+
+| Code                                                   | Output             |
+|-------------------------------------------------------:|:-------------------|
+| {% raw %}`{{ '   too many spaces   ' | lstrip }}`{% endraw %}     | `"too many spaces   "` |

_filters/rstrip.md

@@ -1,3 +1,9 @@
 ---
 title: rstrip
 ---
+
+Strips all whitespace (tabs, spaces, and newlines) from the right side of a string.
+
+| Code                                                   | Output             |
+|-------------------------------------------------------:|:-------------------|
+| {% raw %}`{{ '   too many spaces   ' | rstrip }}`{% endraw %}     | `"too many spaces   "` |

_filters/strip.md

@@ -1,3 +1,9 @@
 ---
 title: strip
 ---
+
+Strips all whitespace (tabs, spaces, and newlines) from a string.
+
+| Code                                                   | Output             |
+|-------------------------------------------------------:|:-------------------|
+| {% raw %}`{{ '   too many spaces   ' | strip }}`{% endraw %}     | `"too many spaces"` |