Fix crash when a sidebar is the first element in a book

[pmachapman]

Fixes sillsdev/serval#829

---

This change is 

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.51%. Comparing base (754c97d) to head (0715464).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #360   +/-   ##
=======================================
  Coverage   72.51%   72.51%           
=======================================
  Files         423      423           
  Lines       35927    35933    +6     
  Branches     4958     4960    +2     
=======================================
+ Hits        26052    26058    +6     
  Misses       8779     8779           
  Partials     1096     1096           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[Enkidu93]

@Enkidu93 reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @ddaspit)

---

src/SIL.Machine/Corpora/ScriptureRefUsfmParserHandlerBase.cs line 175 at r1 (raw file):

        public override void StartSidebar(UsfmParserState state, string marker, string category)
        {
            if (_curVerseRef.IsDefault)

Could something similar happen with other markers?

[ddaspit]

@ddaspit reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @pmachapman)

[pmachapman]

Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @Enkidu93)

---

src/SIL.Machine/Corpora/ScriptureRefUsfmParserHandlerBase.cs line 175 at r1 (raw file):

Previously, Enkidu93 (Eli C. Lowry) wrote…

Could something similar happen with other markers?

Good thinking - yes it could with a table row. I have added a commit to fix this, and a test to confirm.

[ddaspit]

@ddaspit reviewed 2 of 2 files at r2, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @Enkidu93)

[Enkidu93]

@Enkidu93 reviewed 1 of 2 files at r2.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @pmachapman)

---

src/SIL.Machine/Corpora/ScriptureRefUsfmParserHandlerBase.cs line 175 at r1 (raw file):

Previously, pmachapman (Peter Chapman) wrote…

Good thinking - yes it could with a table row. I have added a commit to fix this, and a test to confirm.

Excellent! Save ourselves some time later 😅