docs: Describe using --date-format and --datetime-format to disable t…

…ype inference for dates and datetimes, closes #917

docs/common_arguments.rst

@@ -57,7 +57,7 @@ These arguments can be used to override csvkit's default "smart" parsing of CSV
 
 For example, to disable CSV sniffing, set :code:`--snifflimit 0` and then, if necessary, set the :code:`--delimiter` and :code:`--quotechar` options yourself. Or, set :code:`--snifflimit -1` to use the entire file as the sample, instead of the first 1024 bytes.
 
-To disable type inference, add the :code:`--no-inference` flag.
+To disable type inference, add the :code:`--no-inference` flag. To prevent text values from being converted to dates or datetimes, set the :code:`--date-format` and/or :code:`--datetime-format` options to a non-occurring value, like ``-``.
 
 The output of csvkit's tools is always formatted with "default" formatting options. This means that when executing multiple csvkit commands (either with a pipe or through intermediary files) it is only ever necessary to specify these arguments the first time (and doing so for subsequent commands will likely cause them to fail).
 

docs/tricks.rst

@@ -114,13 +114,16 @@ Although these issues are annoying, in most cases, CSV sniffing Just Works™. D
 CSV data interpretation
 -----------------------
 
-* Are the numbers ``1`` and ``0`` being interepted as ``True`` and ``False``?
+* Are the numbers ``1`` and ``0`` being interpreted as ``True`` and ``False``?
 * Are phone numbers changing to integers and losing their leading ``+`` or ``0``?
+* Are text values incorrectly being converted to dates or datetimes?
 * Is the Italian comune of "None" being treated as a null value?
 
 These may be symptoms of csvkit's type inference being too aggressive for your data. CSV is a text format, but it may contain text representing numbers, dates, booleans or other types. csvkit attempts to reverse engineer that text into proper data types—a process called "type inference".
 
-For some data, type inference can be error prone. If necessary you can disable it with the :code:`--no-inference` switch. This will force all columns to be treated as regular text.
+For some data, type inference can be error prone. If necessary you can disable it with the :code:`--no-inference` option. This will force all columns to be treated as regular text.
+
+To prevent values from being converted to dates or datetimes, set the :code:`--date-format` and/or :code:`--datetime-format` options to a non-occurring value, like ``-``.
 
 Slow performance
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