fix(man): Update man/zetta.1.md

Co-authored-by: sbatial <46973479+sbatial@users.noreply.github.com>

man/zetta.1.md

@@ -192,6 +192,7 @@ ENVIRONMENT VARIABLES
 =====================
 
 Zetta responds to the following environment variables:
+(Note: Compatibility with exa is a priority hence the variable names.)
 
 ## `COLUMNS`