Fix default output directory claim in Beam docs

The default output goes to the project directory (where the .fsproj is),
not ./output.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dbrattli

docs/docs/beam/build-and-run.md

@@ -31,7 +31,7 @@ The generated `.erl` files are standard Erlang that can be compiled with `erlc`
 dotnet fable --lang beam
 ```
 
-By default, output goes to `./output`. You can change this with `--outDir`:
+By default, output goes to the project directory (where the `.fsproj` is). You can change this with `--outDir`:
 
 ```bash
 dotnet fable --lang beam --outDir /path/to/output

docs/docs/getting-started/beam.md

@@ -31,7 +31,7 @@ Compile your project to Erlang:
 dotnet fable --lang beam
 ```
 
-This generates `.erl` files in the output directory (default `./output`).
+This generates `.erl` files in the project directory (where the `.fsproj` is) by default.
 
 </li>