Update text/courses/data-cleaning.rst
Update text/courses/data-cleaning-nuts-and-gum.rst
Update text/courses/data-cleaning-invisible-man-in-spreadsheets.rst
Update text/courses/data-cleaning-invisible-man-in-spreadsheets.rst
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Merge branch 'patch-13' of https://github.com/emmaprest/datawrangling
Merge branch 'patch-12' of https://github.com/emmaprest/datawrangling closes #62
Merge branch 'patch-11' of https://github.com/emmaprest/datawrangling closes #61
Merge branch 'patch-10' of https://github.com/emmaprest/datawrangling closes #60
closes #59 Merge branch 'patch-9' of https://github.com/emmaprest/datawrangling

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	text/courses/data-cleaning.rst