docs update

Author: SpectraL519

docs/graph_elements.md

@@ -164,14 +164,20 @@ The destructor is *defaulted*, allowing proper cleanup of the `edge_descriptor`
 
 - **`incident_vertex(const vertex_type& vertex) const`**:
   - *Description*: Returns the vertex on the other end of the edge relative to the provided vertex. Throws an error if the provided vertex is not incident with the edge.
-  - *Returned value*: $\begin{cases} v & \text{: vertex} = u \\ u & \text{: vertex} = v  \\ \text{error} & \text{: otherwise} \end{cases}$
+  - *Returned value*:
+    - $v$ if $\text{vertex} = u$
+    - $u$ if $\text{vertex} = v$
+    - error otherwise
   - *Parameters*:
     - `vertex: const vertex_type&` – the vertex for which the opposite vertex is requested.
   - *Return type*: `const vertex_type&`
 
 - **`incident_vertex_id(const types::id_type vertex_id) const`**:
   - *Description*: Returns the ID of the vertex on the other end of the edge relative to the provided vertex ID. Throws an error if the provided vertex ID is invalid.
-  - *Returned value*: $\begin{cases} v_{id} & \text{: vertex-id} = u_{id} \\ u_{id} & \text{: vertex-id} = v_{id} \\ \text{error} & \text{: otherwise} \end{cases}$
+  - *Returned value*:
+    - $v_{id}$ if $\text{vertex-id} = u_{id}$
+    - $u_{id}$ if $\text{vertex-id} = v_{id}$
+    - error otherwise
   - *Parameters*:
     - `vertex_id: const types::id_type` – the vertex ID for which the opposite vertex ID is requested.
   - *Return type*: `types::id_type`