[docs] fix typo (#24528)

## Changelog

NOCHANGELOG

docs/content/guides/dagster/enriching-with-software-defined-assets.mdx

@@ -12,7 +12,7 @@ Before we jump in, here's a quick refresher:
 - An **asset** is a persistent object in storage, such as a table, machine learning (ML) model, or file.
 - An [**op**](/concepts/ops-jobs-graphs/ops) is the core unit of computation in Dagster. For example, an op might accept tabular data as its input and produce transformed tabular data as its output.
 - A [**graph**](/concepts/ops-jobs-graphs/graphs) is a directed acyclic graph of ops or other graphs, which execute in order and pass data to each other.
-- Am [**asset definition**](/concepts/assets/software-defined-assets) is a declaration of an asset that should exist and a description of how to compute it: the op or graph that needs to run and the upstream assets that it should run on.
+- An [**asset definition**](/concepts/assets/software-defined-assets) is a declaration of an asset that should exist and a description of how to compute it: the op or graph that needs to run and the upstream assets that it should run on.
 
 **Asset definitions aren't a replacement for Dagster's core computational concepts** - ops are, in fact, the core unit of computation that occurs **within an asset**. Think of them as a top layer that links ops, graphs, and jobs to the long-lived objects they interact with.