[mlir][Python] Roll up of python API fixes.
- As discussed, fixes the ordering or (operands, results) -> (results, operands) in various create like methods.
- Fixes a syntax error in an ODS accessor method.
- Removes the linalg example in favor of a test case that exercises the same.
- Fixes FuncOp visibility to properly use None instead of the empty string and defaults it to None.
- Implements what was documented for requiring that trailing init args loc and ip are keyword only.
- Adds a check to InsertionPoint.insert so that if attempting to insert past the terminator, an exception is raised telling you what to do instead. Previously, this would crash downstream (i.e. when trying to print the resultant module).
- Renames _ods_build_default -> build_generic and documents it.
- Removes result from the list of prohibited words and for single-result ops, defaults to naming the result result, thereby matching expectations and what is already implemented on the base class.
- This was intended to be a relatively small set of changes to be inlined with the broader support for ODS generating the most specific builder, but it spidered out once actually testing various combinations, so rolling up separately.
Differential Revision: https://reviews.llvm.org/D95320