Fix small grammatical errors with coref_resolved

[sam2k13]

Happy to get feedback, but this handles 2 issues I found reducing the quality of the coref_resolved property on the output.

• Don't replace Coref spans with PRONOMINAL spans.

  • It appears "PRONOMINAL" spans (i.e. He, She, They) are contextually lacking and replacing a span with a PRONOMINAL does not improve quality
  • Original Sentence: He likes to eat chocolate. His favorite chocolate is Hershey's.
  • Previously: He likes to eat chocolate. He favorite chocolate is Hershey's.
  • New: He likes to eat chocolate. His favorite chocolate is Hershey's.

• Don't replace spans including a "Determiner" POS tag (DET)

  • Possessive Determiner's are words like: My, your, his, her, their
  • Without resolving punctuation, replacing a "Determiner" with a pronoun can lead to grammatically incorrect sentences. Also, replacing a Determiner in the middle of a sentence often degrades its quality.
    • Example: Joe likes to bring his boat to the lake.
    • Previously: Joe likes to bring Joe boat to the lake.
    • New: Joe likes to bring his boat to the lake.

If any of these changes go against the grain of the desired Coreference resolution, I am open to changes or no need to merge this PR. For my use case, having the resolved Coref text stay high quality is very important.