chore: Sync 'master' into 'devel' (#683)

Automated sync of 'master' into 'devel' after release. Auto-merged when
all checks pass.

Add `concatenate_nth_power` for NFTs (#682)

`concatenate_nth_power` was defined only for NFAs, now it is also
defined for NFTs.

chore: Sync 'master' into 'devel' (#681)

Automated sync of 'master' into 'devel' after release. Auto-merged when
all checks pass.

nft: +refactor +fix Do not append levels twice, reuse NFA union (#680)

This PR makes NFT union reuse the NFA union and fixes an issue where the
vector of levels is appended to the union result NFT twice.

chore: Sync 'master' into 'devel' (#679)

Automated sync of 'master' into 'devel' after release. Auto-merged when
all checks pass.

+chore Add `.clangd` (#678)

Adds `.clangd` which configures where to look for
`compile_commands.json`.

chore: Sync 'master' into 'devel' (#676)

Automated sync of 'master' into 'devel' after release. Auto-merged when
all checks pass.

Issue #613 - fix (#675)

This PR fixes and closes #613.

There was no issue with `create_sigma_star_nft`, contrary to what the
issue suggested. The problem was in the implementation of
`is_in_lang_by_levels`, which is called by `is_in_lang`.

In the case of a jump transition, the method did not use the symbol of
that transition. Instead, it incorrectly used the first symbol of the
input word. As a result, words such as `{'a', 'a'}` correctly passed a
`DONT_CARE` jump transition, but words such as `{'a', 'b'}` were
incorrectly rejected.

Moreover, this bug allowed any word beginning with `DONT_CARE` to be
accepted by any jump transition, which is incorrect. For example, the
word `{DONT_CARE, 'b'}` was accepted by a jump transition over the
repeated symbol `'a'` because every comparison was made against the
first symbol of the word (`DONT_CARE`) instead of the symbol on the
transition.

chore: Sync 'master' into 'devel' (#674)

Automated sync of 'master' into 'devel' after release. Auto-merged when
all checks pass.

nft/composition(fix): Skip recomputing synchronization types (#673)

Skips recomputing synchronisation types of targets of transitions from
states already computed.

Fixes #670. Fixes VeriFIT/z3-noodler#398.