[changelog skip] Added missing backtick on 'unmatched unknown detected'

[mauro-oto]

Adds a missing backtick on unknown in the invalid block banner.

[mauro-oto]

Weird, the test passes locally on 2.6.6, which CI seems to be using for 2.6. I guess we could remove the test, and just fix the typo if you prefer @schneems.

[schneems]

I am seeing a failure locally. I'll dig in now

Failures:

  1) DeadEnd::DisplayInvalidBlocks Unmatched unknown banner
     Failure/Error: expect(display.banner).to include("DeadEnd: Unmatched `unknown` detected")
       expected nil to include "DeadEnd: Unmatched `unknown` detected", but it does not respond to `include?`
     # ./spec/unit/display_invalid_blocks_spec.rb:69:in `block (2 levels) in <module:DeadEnd>'

Finished in 6.61 seconds (files took 0.21497 seconds to load)
84 examples, 1 failure

Failed examples:

rspec ./spec/unit/display_invalid_blocks_spec.rb:54 # DeadEnd::DisplayInvalidBlocks Unmatched unknown banner

[schneems]

In 2.6.6 (for me) case @invalid_obj.error_symbol returns :unknown which is a case we're not handling. We're only handling if case @invalid_obj.unmatched_symbol is unknown.

This failing test accidentally shows an edge case that we're not handling.

[schneems]

It turns out the WhoDisSyntaxError didn't handle a few different syntax cases. I've pushed a commit to your branch to fix the issue.