docs(installation): clarify that ble.sh needs to be loaded in ~/.bashrc

The detailed explanations existed in README.md of the main repository
atuinsh/atuin has been removed by [1] in favor of atuinsh/docs.
However, the installation instructions in atuinsh/docs are not
up-to-date and confuse the users [2].  We should update atuinsh/docs
to pick some of the informatioin removed by [1].

[1] atuinsh/atuin#2203
[2] atuinsh/atuin#1798 (comment)

src/content/docs/guide/installation.mdx

@@ -136,7 +136,7 @@ After installing, remember to restart your shell.
             <TabItem label="ble.sh">
                 Atuin works best in bash when using [ble.sh](https://github.com/akinomyoga/ble.sh).
 
-                With ble.sh installed, just add atuin to your .bashrc
+                With ble.sh installed and loaded in `~/.bashrc`, just add atuin to your `~/.bashrc`
 
                 ```shell
                 echo 'eval "$(atuin init bash)"' >> ~/.bashrc