DOC: Pandas Pg 47 label/61 doc merge() link redirects to first page
#### Location of the documentation

Page 47

[this should provide the location of the documentation, e.g. "pandas.read_csv" or the URL of the documentation, e.g. "https://dev.pandas.io/docs/reference/api/pandas.read_csv.html"]

**Note**: You can check the latest versions of the docs on `master` [here](https://pandas.pydata.org/docs/dev/).

#### Documentation problem

merge() link is broken and links back to the first page

[this should provide a description of what documentation you believe needs to be fixed/improved]

#### Suggested fix for documentation

[this should explain the suggested fix and **why** it's better than the existing documentation]
