feat(docs): add more detailed description

README.md

@@ -1,5 +1,17 @@
 # rtp.nvim
 
-Source plugin and ftdetect directories on the Neovim runtimepath.
+Source `plugin` and `ftdetect` directories on the Neovim `:h runtimepath`.
 
-See the [API reference](./doc/rtp_nvim.txt) for details.
+If you install plugins to a different location than the `:h packpath`,
+you can use this library to source their
+`plugin`, `ftdetect` and `after-directory` scripts.
+
+The main use cases are:
+
+- As a dependency for plugin managers,
+  such as [rocks-dev.nvim](https://github.com/nvim-neorocks/rocks-dev.nvim).
+- For use with lazy-loading utilities,
+  such as [rocks-lazy.nvim](https://github.com/nvim-neorocks/rocks-lazy.nvim)
+  or [lz.n](https://github.com/nvim-neorocks/lz.n).
+
+See the [API reference](./doc/rtp_nvim.txt) for documentation.

doc/rtp_nvim.txt

@@ -4,6 +4,9 @@
 
 Source |plugin| and |ftdetect| directories on the Neovim runtimepath
 
+If you install plugins to a different location than the |packpath|,
+you can use this library to source their
+|plugin|, |ftdetect| and |after-directory| scripts.
 
 rtp_nvim.source_rtp_dir({dir})                         *rtp_nvim.source_rtp_dir*
     Source the `plugin` and `ftdetect` directories.

lua/rtp_nvim.lua

@@ -4,6 +4,9 @@
 ---
 ---Source |plugin| and |ftdetect| directories on the Neovim runtimepath
 ---
+---If you install plugins to a different location than the |packpath|,
+---you can use this library to source their
+---|plugin|, |ftdetect| and |after-directory| scripts.
 ---@brief ]]
 
 -- Copyright (C) 2024 Neorocks Org.