replace user-facing references to "sbd" with "sentencizer" (#2985)

## Description
Fixes #2693
Previously, the tokens `sbd` and `sentencizer` would create the same nlp pipe. Internally, both would be called `sbd`. This setup became problematic because it was hard for a user relying on the `sentencizer` pipe name to realize that their pipe's name would be `sbd` for all functions other than creating a pipe. This PR intends to change the API and API documentation to fully support `sentencizer` and drop any user-facing references to `sbd`.

### Types of change
end-user API bug

## Checklist
<!--- Before you submit the PR, go over this checklist and make sure you can
tick off all the boxes. [] -> [x] -->
- [x] I have submitted the spaCy Contributor Agreement.
- [x] I ran the tests, and all new and existing tests passed.
- [x] My changes don't require a change to the documentation, or if they do, I've added all required information.

.github/contributors/gavrieltal.md

@@ -0,0 +1,106 @@
+# spaCy contributor agreement
+
+This spaCy Contributor Agreement (**"SCA"**) is based on the
+[Oracle Contributor Agreement](http://www.oracle.com/technetwork/oca-405177.pdf).
+The SCA applies to any contribution that you make to any product or project
+managed by us (the **"project"**), and sets out the intellectual property rights
+you grant to us in the contributed materials. The term **"us"** shall mean
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+**"you"** shall mean the person or entity identified below.
+
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+## Contributor Agreement
+
+1. The term "contribution" or "contributed materials" means any source code,
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+
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+
+    * you hereby assign to us joint ownership, and to the extent that such
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+
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+7. Please place an “x” on one of the applicable statement below. Please do NOT
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+    * [] I am signing on behalf of my employer or a legal entity and I have the
+    actual authority to contractually bind that entity.
+
+## Contributor Details
+
+| Field                          | Entry                |
+|------------------------------- | -------------------- |
+| Name                           | Gavriel Loria        |
+| Company name (if applicable)   |                      |
+| Title or role (if applicable)  |                      |
+| Date                           | Nov 29, 2018         |
+| GitHub username                | gavrieltal           |
+| Website (optional)             |                      |

spacy/errors.py

@@ -284,6 +284,9 @@ class Errors(object):
     E106 = ("Can't find doc._.{attr} attribute specified in the underscore "
             "settings: {opts}")
     E107 = ("Value of doc._.{attr} is not JSON-serializable: {value}")
+    E108 = ("As of spaCy v2.1, the pipe name `sbd` has been deprecated "
+            "in favor of the pipe name `sentencizer`, which does the same "
+            "thing. For example, use `nlp.create_pipeline('sentencizer')`")
 
 
 @add_codes

spacy/language.py

@@ -116,7 +116,6 @@ class Language(object):
         "ner": lambda nlp, **cfg: EntityRecognizer(nlp.vocab, **cfg),
         "similarity": lambda nlp, **cfg: SimilarityHook(nlp.vocab, **cfg),
         "textcat": lambda nlp, **cfg: TextCategorizer(nlp.vocab, **cfg),
-        "sbd": lambda nlp, **cfg: SentenceSegmenter(nlp.vocab, **cfg),
         "sentencizer": lambda nlp, **cfg: SentenceSegmenter(nlp.vocab, **cfg),
         "merge_noun_chunks": lambda nlp, **cfg: merge_noun_chunks,
         "merge_entities": lambda nlp, **cfg: merge_entities,
@@ -243,6 +242,9 @@ class Language(object):
         RETURNS (callable): Pipeline component.
         """
         if name not in self.factories:
+            if name == "sbd":
+                raise KeyError(Errors.E108.format(name=name))
+            else:
                 raise KeyError(Errors.E002.format(name=name))
         factory = self.factories[name]
         return factory(self, **config)

spacy/pipeline.pyx

@@ -49,7 +49,7 @@ class SentenceSegmenter(object):
     Sentence detection strategies should be generators that take `Doc` objects
     and yield `Span` objects for each sentence.
     """
-    name = 'sbd'
+    name = 'sentencizer'
 
     def __init__(self, vocab, strategy=None):
         self.vocab = vocab

website/usage/_linguistic-features/_sentence-segmentation.jade

@@ -88,8 +88,8 @@ p
     from spacy.lang.en import English
 
     nlp = English()  # just the language with no model
-    sbd = nlp.create_pipe('sentencizer')   # or: nlp.create_pipe('sbd')
-    nlp.add_pipe(sbd)
+    sentencizer = nlp.create_pipe('sentencizer')
+    nlp.add_pipe(sentencizer)
     doc = nlp(u"This is a sentence. This is another sentence.")
     for sent in doc.sents:
         print(sent.text)
@@ -122,8 +122,8 @@ p
             yield doc[start:len(doc)]
 
     nlp = English()  # just the language with no model
-    sbd = SentenceSegmenter(nlp.vocab, strategy=split_on_newlines)
-    nlp.add_pipe(sbd)
+    sentencizer = SentenceSegmenter(nlp.vocab, strategy=split_on_newlines)
+    nlp.add_pipe(sentencizer)
     doc = nlp(u"This is a sentence\n\nThis is another sentence\nAnd more")
     for sent in doc.sents:
         print([token.text for token in sent])

website/usage/_processing-pipelines/_extensions.jade

@@ -144,7 +144,7 @@ p
 +code-exec.
     import spacy
 
-    def sbd_component(doc):
+    def custom_sentencizer(doc):
         for i, token in enumerate(doc[:-2]):
             # define sentence start if period + titlecase token
             if token.text == '.' and doc[i+1].is_title:
@@ -152,7 +152,7 @@ p
         return doc
 
     nlp = spacy.load('en_core_web_sm')
-    nlp.add_pipe(sbd_component, before='parser')  # insert before the parser
+    nlp.add_pipe(custom_sentencizer, before='parser') # insert before parser
     doc = nlp(u"This is a sentence. This is another sentence.")
     for sent in doc.sents:
         print(sent.text)