Unify syntax translations for shallow embedding of callables

It seems that for each of our three(/four?) `urust_callable` grammar entries and each of the ways to call them, we have a separate syntax translation.

For example, these are the syntax translations for a regular function call with arguments (`_urust_funcall_with_args`):

https://github.com/awslabs/AutoCorrode/blob/7bb1e284f9e51bf55dd199301035ee27137ab242/Shallow_Micro_Rust/Micro_Rust_Shallow_Embedding.thy#L299-L306

Note that each one corresponds to an entry in the `_urust_callable` grammar.
For a function call without arguments (`_urust_funcall_no_args`), we have

https://github.com/awslabs/AutoCorrode/blob/7bb1e284f9e51bf55dd199301035ee27137ab242/Shallow_Micro_Rust/Micro_Rust_Shallow_Embedding.thy#L329-L335

with an entry for all `_urust_callable` grammare entries (except `_urust_embed_antiquotation`, which I think never appears without arguments).

It seems to me that these could/should be unified, into a _single_ rule for each of the ways to call a function, and a _single_ rule for each of the ways to shallowly embed the called function. This should improve readability and extensibility.

Read Shallow_Micro_Rust/Micro_Rust_Shallow_Embedding.thy, especially the _urust_funcall_with_args rules around lines 299-306 and _urust_funcall_no_args around 329-335. Compare these with the _urust_callable grammar entries and the shallow-embedding call forms. Done means the duplicated translations are unified while all listed callable forms remain supported.

Written by the indexing model from the issue text.