docs: Update elvish configuration description (#7054)

README.md

@@ -307,13 +307,13 @@ load(io.popen('starship init cmd'):read("*a"))()
 <details>
 <summary>Elvish</summary>
 
-Add the following to the end of `~/.elvish/rc.elv`:
+Add the following to the end of `~/.config/elvish/rc.elv` (`%AppData%\elvish\rc.elv` on Windows):
 
 ```sh
 eval (starship init elvish)
 ```
 
-Note: Only Elvish v0.18+ is supported
+Note: Only Elvish v0.18+ is supported. For elvish versions prior to v0.21.0 the config file might instead be `~/.elvish/rc.elv`
 
 </details>
 

docs/README.md

@@ -127,13 +127,14 @@ onMounted(() => {
    > [!WARNING]
    > Only elvish v0.18 or higher is supported.
 
-   Add the following to the end of `~/.elvish/rc.elv`:
+   Add the following to the end of `~/.config/elvish/rc.elv` (`%AppData%\elvish\rc.elv` on Windows):
 
    ```sh
    # ~/.elvish/rc.elv
 
    eval (starship init elvish)
    ```
+   For elvish versions prior to v0.21.0 the config file might instead be `~/.elvish/rc.elv`
 
    #### Tcsh
 

install/install.sh

@@ -371,7 +371,7 @@ print_install() {
     case ${s} in
       elvish )
         # shellcheck disable=SC2088
-        config_file="~/.elvish/rc.elv"
+        config_file="~/.config/elvish/rc.elv"
         config_cmd="eval (starship init elvish)"
         warning="${warning} Only elvish v0.17 or higher is supported."
         ;;