Revert "Remove markdown from git tracking (#139)"

This reverts commit bbb6e3f309.

markdown/bitburner.hacknet.upgradecache.md

@@ -0,0 +1,39 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [bitburner](./bitburner.md) &gt; [Hacknet](./bitburner.hacknet.md) &gt; [upgradeCache](./bitburner.hacknet.upgradecache.md)
+
+## Hacknet.upgradeCache() method
+
+Upgrade the cache of a hacknet node.
+
+<b>Signature:</b>
+
+```typescript
+upgradeCache(index: number, n: number): boolean;
+```
+
+## Parameters
+
+|  Parameter | Type | Description |
+|  --- | --- | --- |
+|  index | number | Index/Identifier of Hacknet Node. |
+|  n | number | Number of cache levels to purchase. Must be positive. Rounded to nearest integer. |
+
+<b>Returns:</b>
+
+boolean
+
+True if the Hacknet Node’s cache level is successfully upgraded, false otherwise.
+
+## Remarks
+
+RAM cost: 0 GB
+
+This function is only applicable for Hacknet Servers (the upgraded version of a Hacknet Node).
+
+Tries to upgrade the specified Hacknet Server’s cache n times.
+
+Returns true if it successfully upgrades the Server’s cache n times, or if it purchases some positive amount and the Server reaches its max cache level.
+
+Returns false otherwise.
+