Results 3 issues of apalermo01

## Description First time contributor here (both to pymc and open source) - updated docstrings in pymc.model.core.Model to follow numpydoc. There are some details that I need to call out....

When I run add_text, no text appears in the selected rectangle. Here's my config: ```config startup_commands toggle_custom_color new_command _embed_annotations_in_file python /home/alex/scripts/embed_annotations_in_file.py %{sioyek_path} %{local_database} %{shared_database} %{file_path} new_command _add_text python -m sioyek.add_text...

Bash is not in /bin on nixos so tpm was returning a 127 error. I updated the shebang to #!/usr/env/bin bash to be more compatible.