See #103

…te string

See #109 for context

Promote multiple --file assert to log_error
Why? It's a usage error we're communicating to the user, not a code invariant we're checking in debug mode.
We could recover, but we don't, because we expect only automated usage and want to give clear feedback.

More pythonic if

Improve my --file flag messaging consistency

Call library to escape regex
Helps avoid edge cases! Also handles the most common special character, '.'

Add an error to catch unsupported --file <file> form

Tweak -- logic now that --file arguments could be after

--file docs

Make aquery spacing consistent

Flip the if statement in constructor target_statment

Use let to combine attr query

Merge compile_commands.json if --file

Small simplification: endswith already can take a tuple of possibilities (as elsewhere)

Small simplification of header path for file flag.
(This code section likely to be replaced later, though.)

Fix my typo on --file= discoverable docs

Some tweaks to merge
Adds note about behavior, some edge case handling around other flags that might start with --file, permissions issues, etc.