Fix starting element error when analyzing corpora

[Enkidu93]

Fixes #324

• Consistently use text elements for indexing and string length
• Add manual test for running quote convention analysis

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This change is 

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.20%. Comparing base (8e35c45) to head (36ec6b6).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #325   +/-   ##
=======================================
  Coverage   72.19%   72.20%           
=======================================
  Files         414      414           
  Lines       35144    35154   +10     
  Branches     4862     4865    +3     
=======================================
+ Hits        25373    25383   +10     
  Misses       8679     8679           
  Partials     1092     1092           

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[Enkidu93]

Reviewable status: 0 of 4 files reviewed, 1 unresolved discussion (waiting on @ddaspit)

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src/SIL.Machine/PunctuationAnalysis/QuotationMarkFinder.cs line 50 at r1 (raw file):

                .Select(m =>
                {
                    int[] textElementBeginnings = StringInfo.ParseCombiningCharacters(textSegment.Text);

This could be made more efficient, but I'm not sure how much of a difference it'd really make.

[ddaspit]

Can we add a unit test to cover this case?

@ddaspit reviewed 4 of 4 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion

[Enkidu93]

Done.

Reviewable status: 3 of 6 files reviewed, 1 unresolved discussion (waiting on @ddaspit)

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src/SIL.Machine/PunctuationAnalysis/QuotationMarkFinder.cs line 50 at r1 (raw file):

Previously, Enkidu93 (Eli C. Lowry) wrote…

This could be made more efficient, but I'm not sure how much of a difference it'd really make.

I just went ahead and did it.

[ddaspit]

@ddaspit reviewed 3 of 3 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @Enkidu93)