docs: add extra docs for .juliabundleignore

Author: mortenpi

docs/src/reference/job-submission.md

@@ -137,10 +137,19 @@ More precisely, it uses [Glob.jl](https://github.com/vtjnash/Glob.jl) to match t
 For example, a valid `.juliabundleignore` might contain the following entries to exclude a particular directory and all CSV files:
 
 ```
+output.log
 *.csv
 output-data/
 ```
 
+This `.juliabundleignore` will ignore:
+
+- The `output.log` file next to the `.juliabundleignore`.
+- All `.csv` files next to the `.juliabundleignore` and in subdirectories.
+- All the contents of the `output-data/` directory next to the `.juliabundleignore`.
+
+You can also have additional `.juliabundleignore` files in subdirectories and they will only apply to those directories and their subdirectories.
+
 ### Specifying the job image
 
 JuliaHub batch jobs can run in various container images.

test/fixtures/bundle1/Manifest.toml

@@ -0,0 +1,7 @@
+# This file is machine-generated - editing it directly is not advised
+
+julia_version = "1.12.0-rc1"
+manifest_format = "2.0"
+project_hash = "71853c6197a6a7f222db0f1978c7cb232b87c5ee"
+
+[deps]

test/fixtures/bundle1/Project.toml

@@ -0,0 +1 @@
+[deps]