Rename syntax definitions

Duplicate syntax definition names may cause problems.
Since nano comes with predefined all-lowercase syntax definitions,
we use uppercase letters everywhere to reduce the risk of future conflicts

fish.nanorc

@@ -1,6 +1,6 @@
 ## Here is an example for Fish shell scripts.
 ##
-syntax "fish" "\.fish$"
+syntax "Fish" "\.fish$"
 icolor brightgreen "^[0-9A-Z_]+\(\)"
 color green "\<(alias|begin|break|case|continue|contains|else|end|for|function|if|math|return|set|switch|test|while)\>"
 color green "(\{|\}|\(|\)|\;|\]|\[|`|\\|\$|<|>|!|=|&|\|)"