ContextualMenu and Dropdown doc comment updates

[ecraig12345]

Pull request checklist

• Addresses an existing issue: Fixes Menu of CommandButton not dismissed as documented #13339, fixes Incorrect documentation for Dropdown component #12848
• Include a change request file using $ yarn change

Description of changes

Clarify issues with IContextualMenuItem.onClick and IDropdownProps.selectedKeys docs that came up in shield issues. (Plus cleanup of some other props' docs.)

[msft-github-bot]

Perf Analysis

No significant results to display.

All results

Scenario	Master Ticks	PR Ticks	Iterations	Status
BaseButton	825	865	5000
ButtonNext	405	386	5000
Checkbox	1607	1558	5000
CheckboxBase	1381	1381	5000
CheckboxNext	1596	1600	5000
ChoiceGroup	4955	4896	5000
ComboBox	904	935	1000
CommandBar	7421	7440	1000
ContextualMenu	11893	11842	1000
DefaultButton	1057	1069	5000
DetailsRow	3417	3575	5000
DetailsRow (fast icons)	3393	3418	5000
DetailsRow without styles	3285	3237	5000
Dialog	1549	1507	1000
DocumentCardTitle with truncation	1855	1841	1000
Dropdown	2437	2418	5000
FocusZone	1652	1667	5000
IconButton	1714	1763	5000
Label	292	316	5000
Link	463	474	5000
LinkNext	450	497	5000
MenuButton	1450	1389	5000
Nav	3202	3218	1000
Panel	1430	1453	1000
Persona	787	850	1000
Pivot	1365	1381	1000
PivotNext	772	793	5000
PrimaryButton	1256	1221	5000
SearchBox	1294	1342	5000
Slider	1474	1447	5000
SliderNext	1885	1899	5000
Spinner	373	393	5000
SplitButton	3075	3036	5000
Stack	473	465	5000
Stack with Intrinsic children	1794	1782	5000
Stack with Text children	4950	5080	5000
TagPicker	2753	2711	5000
Text	407	403	5000
TextField	1392	1384	5000
ThemeProvider	2672	2737	5000
Toggle	878	868	5000
ToggleNext	844	888	5000
button	78	69	5000

Perf Analysis (Fluent)

Perf comparison

Status	Scenario	Fluent TPI	Fabric TPI	Ratio	Iterations	Ticks
🎯	Avatar.Fluent	0.49	0.49	1:1	2000	974
🦄	Button.Fluent	0.11	0.19	0.58:1	5000	564
🔧	Checkbox.Fluent	0.61	0.33	1.85:1	1000	607
🦄	Dialog.Fluent	0.14	0.21	0.67:1	5000	717
🔧	Dropdown.Fluent	3.17	0.44	7.2:1	1000	3167
🔧	Icon.Fluent	0.13	0.05	2.6:1	5000	670
🦄	Image.Fluent	0.07	0.11	0.64:1	5000	352
🔧	Slider.Fluent	1.51	0.33	4.58:1	1000	1509
🔧	Text.Fluent	0.07	0.02	3.5:1	5000	345
🦄	Tooltip.Fluent	0.09	15.39	0.01:1	5000	433

🔧 Needs work     🎯 On target     🦄 Amazing

Perf tests with no regressions

Scenario	Current PR Ticks	Baseline Ticks	Ratio
AccordionMinimalPerf.default	154	132	1.17:1
CardMinimalPerf.default	615	558	1.1:1
IconMinimalPerf.default	707	645	1.1:1
AnimationMinimalPerf.default	643	594	1.08:1
AvatarMinimalPerf.default	485	455	1.07:1
DividerMinimalPerf.default	358	336	1.07:1
FlexMinimalPerf.default	310	290	1.07:1
ItemLayoutMinimalPerf.default	1388	1300	1.07:1
RadioGroupMinimalPerf.default	436	409	1.07:1
AlertMinimalPerf.default	302	284	1.06:1
MenuButtonMinimalPerf.default	1297	1229	1.06:1
TooltipMinimalPerf.default	752	711	1.06:1
Avatar.Fluent	974	922	1.06:1
HierarchicalTreeMinimalPerf.default	452	429	1.05:1
LayoutMinimalPerf.default	418	397	1.05:1
LoaderMinimalPerf.default	709	676	1.05:1
MenuMinimalPerf.default	869	827	1.05:1
Button.Fluent	564	537	1.05:1
ChatWithPopoverPerf.default	448	432	1.04:1
DropdownManyItemsPerf.default	1351	1300	1.04:1
PortalMinimalPerf.default	115	111	1.04:1
ProviderMergeThemesPerf.default	2017	1941	1.04:1
TableMinimalPerf.default	416	400	1.04:1
TreeWith60ListItems.default	214	205	1.04:1
Checkbox.Fluent	607	584	1.04:1
ButtonSlotsPerf.default	622	603	1.03:1
HeaderMinimalPerf.default	381	371	1.03:1
ListMinimalPerf.default	479	463	1.03:1
TextAreaMinimalPerf.default	482	466	1.03:1
AttachmentMinimalPerf.default	163	160	1.02:1
DialogMinimalPerf.default	742	730	1.02:1
HeaderSlotsPerf.default	815	798	1.02:1
InputMinimalPerf.default	1009	989	1.02:1
RefMinimalPerf.default	184	180	1.02:1
CustomToolbarPrototype.default	3822	3741	1.02:1
Dropdown.Fluent	3167	3113	1.02:1
ChatDuplicateMessagesPerf.default	418	414	1.01:1
CheckboxMinimalPerf.default	2765	2744	1.01:1
ListWith60ListItems.default	1102	1088	1.01:1
TableManyItemsPerf.default	2246	2216	1.01:1
Slider.Fluent	1509	1490	1.01:1
Text.Fluent	345	340	1.01:1
BoxMinimalPerf.default	351	352	1:1
DropdownMinimalPerf.default	3201	3210	1:1
EmbedMinimalPerf.default	1906	1906	1:1
GridMinimalPerf.default	713	716	1:1
ListCommonPerf.default	941	939	1:1
ReactionMinimalPerf.default	402	400	1:1
TextMinimalPerf.default	356	357	1:1
TreeMinimalPerf.default	848	847	1:1
CarouselMinimalPerf.default	447	451	0.99:1
ChatMinimalPerf.default	601	605	0.99:1
LabelMinimalPerf.default	407	412	0.99:1
StatusMinimalPerf.default	661	670	0.99:1
ToolbarMinimalPerf.default	907	913	0.99:1
VideoMinimalPerf.default	615	621	0.99:1
SegmentMinimalPerf.default	340	346	0.98:1
SplitButtonMinimalPerf.default	3400	3464	0.98:1
Dialog.Fluent	717	729	0.98:1
ButtonMinimalPerf.default	169	174	0.97:1
FormMinimalPerf.default	415	430	0.97:1
ListNestedPerf.default	868	891	0.97:1
PopupMinimalPerf.default	252	260	0.97:1
ProviderMinimalPerf.default	817	842	0.97:1
AttachmentSlotsPerf.default	1102	1151	0.96:1
SliderMinimalPerf.default	1479	1539	0.96:1
ImageMinimalPerf.default	355	377	0.94:1
Icon.Fluent	670	716	0.94:1
Image.Fluent	352	381	0.92:1
Tooltip.Fluent	433	474	0.91:1

[size-auditor]

Asset size changes

Size Auditor did not detect a change in bundle size for any component!

Baseline commit: fb6496e5deebdebd955fccf500f2e3f923b0a160 (build)

[msft-github-bot]

🎉office-ui-fabric-react@v7.118.0 has been released which incorporates this pull request.:tada:

Handy links:

• Release Notes
• Official NPM Release
• Test the release with Developer Demo Site