Change hashes link to our new concepts doc

We didn't have our own documentation on hashes when this document was originally written. Now we do, so link to it!

License: MIT
Signed-off-by: Rob Brackett <[email protected]>

Author: Mr0grog

content/introduction/overview.md

@@ -55,7 +55,7 @@ Traditional URLs and file paths like…
 
 …identify a file by *where it’s located* — what computer it’s on and where on that computer’s hard drive it is. That doesn’t work if the file is in many places, though, like your neighbor’s computer and your friend’s across town.
 
-Instead of being location-based, IPFS addresses a file by *what’s in it*, or by it’s *content*. The content identifier above is a *hash* of the content at that address, which means it’s also unique to that content, even though it’s [relatively] short. It also allows you to verify you got what you asked for — bad actors can’t just hand you content that doesn’t match. (If hashes are new to you, check out this article for good introduction: https://tiptopsecurity.com/what-is-cryptographic-hashing-md5-sha-and-more/)
+Instead of being location-based, IPFS addresses a file by *what’s in it*, or by it’s *content*. The content identifier above is a *hash* of the content at that address, which means it’s also unique to that content, even though it’s [relatively] short. It also allows you to verify you got what you asked for — bad actors can’t just hand you content that doesn’t match. (If hashes are new to you, check out [the concept guide on hashes]({{<relref "guides/concepts/hashes.md">}}) for a good introduction.)
 
 <aside class="alert alert-info">
   Why do we say “content” instead of “files” or “web pages” here? In order to make the storage & transmission of data more efficient, IPFS can break files up in to many smaller pieces — which then means the system needs some metadata to tie them back together. An IPFS address can refer to the metadata of just a single piece of a file, a whole file, a directory, a whole website, or even other kinds of data. There’s no single kind of thing that content identifier identifies.