Fix showing aws prompt out of the box for 'fishy' theme (#7747)

This fixes the RPROMPT setting for fishy theme so as to preserve its old value,
instead of overwriting it like it did before.

Also, fix unnecessary export of RPROMPT in aws plugin.

plugins/aws/README.md

@@ -25,6 +25,8 @@ plugins=(... aws)
 ## Plugin options
 
 * Set `SHOW_AWS_PROMPT=false` in your zshrc file if you want to prevent the plugin from modifying your RPROMPT.
+  Some themes might overwrite the value of RPROMPT instead of appending to it, so they'll need to be fixed to
+  see the AWS profile prompt.
 
 ## Theme
 

plugins/aws/aws.plugin.zsh

@@ -44,7 +44,7 @@ function aws_prompt_info() {
 }
 
 if [ "$SHOW_AWS_PROMPT" != false ]; then
-  export RPROMPT='$(aws_prompt_info)'"$RPROMPT"
+  RPROMPT='$(aws_prompt_info)'"$RPROMPT"
 fi
 
 

themes/fishy.zsh-theme

@@ -14,7 +14,7 @@ PROMPT='%n@%m %{$fg[$user_color]%}$(_fishy_collapsed_wd)%{$reset_color%}%(!.#.>)
 PROMPT2='%{$fg[red]%}\ %{$reset_color%}'
 
 local return_status="%{$fg_bold[red]%}%(?..%?)%{$reset_color%}"
-RPROMPT='${return_status}$(git_prompt_info)$(git_prompt_status)%{$reset_color%}'
+RPROMPT="${RPROMPT}"'${return_status}$(git_prompt_info)$(git_prompt_status)%{$reset_color%}'
 
 ZSH_THEME_GIT_PROMPT_PREFIX=" "
 ZSH_THEME_GIT_PROMPT_SUFFIX=""