Merge pull request #150 from ccho-mongodb/CMOS-capitalization-colon-addition

Added CMOS quote for additional guidance on capitalization after colons

Author: Chris Cho

source/style-guide/style/punctuation.txt

@@ -60,6 +60,11 @@ Use the following guidelines for colons:
 - If a title or heading includes a colon, capitalize the first word
   that follows the colon, regardless of its part of speech.
 
+- When you use a colon in a sentence, use lowercase for the first word
+  that follows the colon unless it is a proper noun. When the colon
+  introduces two or more sentences, a quotation, or question, capitalize
+  the first word after the colon (from the Chicago Manual of Style 6.63, v17).
+
 Commas
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