Improve aws profile autocomplete (#1)

* Improve aws profile autocomplete

look in config also;
merge findings and return unique ones;

* Move sed line to current/correct place

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Co-authored-by: Roman Zhuzha <roman.zhuzha@trivago.com>
Co-authored-by: Pablo Santiago Blum de Aguiar <scorphus@gmail.com>

functions/aws.fish

@@ -11,7 +11,7 @@ function aws -a cmd -d 'Universal CLI for AWS'
       end
 
     case profiles
-      command sed -n -e 's/^\[\(.*\)\]/\1/p' "$HOME/.aws/credentials"
+      command sed -n "s/^\[\(profile[[:space:]]*\)*\(.*\)\]/\2/p" "$HOME/.aws/config" "$HOME/.aws/credentials" | sort | uniq
 
     case '*'
       command aws $argv