Add section on slot amount

Signed-off-by: GitHub <noreply@github.com>

Author: ryanlua

docs/assets/hotbar-inventory-full.png

@@ -2,9 +2,9 @@ Through source code modifications, you can change Purse's behavior and appearanc
 
 ## Changing Equip Color
 
-You can make the slot's equip color which is blue, by changing the `SLOT_EQUIP_COLOR` constant in it's source.
+You can change the slot's equip color which is blue, by modifying the `SLOT_EQUIP_COLOR` constant in its source.
 
-This code sample changes the equip color to red.
+The following code sample changes the equip color to red.
 
 ``` lua linenums="44" hl_lines="2"
 --8<-- "src/init.luau:44:44"
@@ -15,3 +15,44 @@ local SLOT_EQUIP_COLOR = Color3.new(233 / 255, 90 / 255, 90 / 255) -- (1)!
 1.  Changed from blue `#!lua Color3.new(90 / 255, 142 / 255, 233 / 255)` to red `#!lua Color3.new(90 / 255, 142 / 255, 233 / 255)`
 
 ![Screenshot of the hotbar with a slot equipped with a red selection outline](assets/red-slot-equip-color.png)
+
+## Increasing Hotbar Slots and Inventory Rows
+
+Purse shows a set number of hotbar slots and inventory rows based on the device.
+
+![Screenshot of the hotbar and inventory with full size](assets/hotbar-inventory-full.png)
+/// caption
+Computer, console, and VR have 10 hotbar slots and 4 inventory rows
+///
+
+![Screenshot of the hotbar and inventory with mini size](assets/hotbar-inventory-mini.png)
+/// caption
+Phone and tablet devices have 3 hotbar slots and 2 inventory rows
+///
+
+It's possible to increase the number of hotbar slots and inventory rows shown by changing the constants in the source code.
+
+!!! note
+
+    Formerly VR devices used different constants for hotbar slots and inventory rows but now use the same as computer and console devices.
+
+    `HOTBAR_SLOTS_VR` and `INVENTORY_ROWS_VR` are no longer used but are still included in the code. VR devices now use `INVENTORY_ROWS_FULL` and `HOTBAR_SLOTS_FULL`.
+
+``` lua linenums="62"
+--8<-- "src/init.luau:62:72"
+```
+
+Constants suffixed with `_FULL` are for computer, console, and VR devices while constants suffixed with `_MINI` are for phone and tablet devices.
+
+The following code sample changes phone and tablet devices to have 5 hotbar slots.
+
+``` lua linenums="62" hl_lines="3"
+--8<-- "src/init.luau:62:63"
+local HOTBAR_SLOTS_MINI = 5 -- (1)!
+--8<-- "src/init.luau:65:66"
+```
+
+1.  Changed from 3 hotbar slots to 5 hotbar slots
+
+![Screenshot of the hotbar and inventory with modified mini size](assets/hotbar-inventory-sample.png)
+

docs/assets/hotbar-inventory-mini.png

@@ -4,7 +4,7 @@ The basic rundown is that **Purse aims to be as close to the CoreGui** while **S
 
   [Satchel]: https://satchel.luau.page
 
-## Design principles
+## Design Principles
 
 * **As close to CoreGui as possible**: Purse aims to be as similar to Roblox's CoreGui as possible so players barely notice the difference
 * **Sync with upstream**: We document changes and keep track of any deviations from the [CoreGui Backpack upstream] which allows us to easily sync to the upstream.

docs/assets/hotbar-inventory-sample.png

@@ -54,6 +54,7 @@ markdown_extensions:
   - attr_list
   - toc:
       permalink: true
+  - pymdownx.blocks.caption
   - pymdownx.snippets
   - pymdownx.superfences
   - pymdownx.inlinehilite