docs: Add 'cygwin' to reference table for .system()
This aligns this table with the set of values tested for by test case
common/140
@@ -55,6 +55,7 @@ These are provided by the `.system()` method call.
| linux | |
| darwin | Either OSX or iOS |
| windows | Any version of Windows |
+| cygwin | The Cygwin environment for Windows |
Any string not listed above is not guaranteed to remain stable in
future releases.
\ No newline at end of file
