Update non-free software description

Fixes https://github.com/awesome-selfhosted/awesome-selfhosted/issues/2721

non-free.md

@@ -1,6 +1,6 @@
-# Awesome Selfhosted - Proprietary Software
+# Awesome Selfhosted - Non-Free Software
 
-**Software listed here does not allow you to run it for any purpose, study, modify or distribute the source code.** Some of the software here may not be audited due to its closed source nature, and can therefore contain anti-features, such as but not limited to: undisclosed security vulnerabilities, backdoors, user lock-in, sending personal data to a third party.
+**Software listed here does not meet the [Free Software](https://en.wikipedia.org/wiki/Free_software) definition**. It implements their own licensing with restrictions and grants which you must check on each case. Restrictions may include limits on allowed use of the software, access to the source code, modification and further redistribution. This software can therefore contain anti user-freedom features, such as but not limited to: backdoors, user lock-in, sending personal data to a third party.
 
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