FIX: Documentation for for 0.14.1 change log

Missing code reference in change log documentation
BUG: PeriodIndex.unique results in Int64Index
Merge pull request #7845 from jreback/setting_with_copy

COMPAT: SettingWithCopy will now warn when slices which can generate views are then set
Merge pull request #7843 from sinhrks/punique

BUG: PeriodIndex.unique results in Int64Index
BUG/VIS: rot and fontsize are not applied to minor ticks
CLN: cln tslib, frequencies
BUG: don't force date parsing in read_html

Necessitates the deprecation of the ``infer_types`` argument.
Merge pull request #7851 from cpcloud/read-html-date-parsing

BUG: fix greedy date parsing in read_html
Merge pull request #7854 from sinhrks/tslib_cln

CLN: Clean tslib, frequencies import
Merge pull request #7844 from sinhrks/minor_rot

BUG/VIS: rot and fontsize are not applied to timeseries plots
Merge pull request #7769 from bashtage/doc-stata-fix

FIX: Documentation for for 0.14.1 change log
Docs: improve installation instructions, recommend Anaconda.
Merge pull request #7849 from lexual/docs_install_conda_wakari

Docs: improve installation instructions, recommend Anaconda.
BUG: Bug in multi-index slicing with missing indexers (GH7866)
BUG: fix multi-column sort that includes Categoricals (GH7848)
CLN: refactor _lexsort_indexer to use Categoricals
BUG: Categorical concat should preserve levels (GH7864)
Merge pull request #7850 from jreback/cat_sort

BUG: fix multi-column sort that includes Categoricals / concat (GH7848/GH7864)
PERF: groupby / frame apply optimization
NETWORK: change failing FRED test
Merge pull request #7881 from jreback/apply_optimize

PERF: groupby / frame apply optimization