Update list of autocomplete layers

autocomplete.md

@@ -84,18 +84,20 @@ without `sources=openaddresses` you will find the most popular Pennsylvanias fir
 ### Layers
 The type of record is referred to as its `layer`. All records are indexed into the following layers:
 
-* `venue`
+|layer|description|
-* `address`
+|----|----|
-* `microhood`
+|`venue`|points of interest, businesses, things with walls|
-* `neighbourhood`
+|`address`|places with a street address|
-* `macrohood`
+|`country`|places that issue passports, nations, nation-states|
-* `county`
+|`macroregion`|a related group of regions. Mostly in Europe|
-* `macrocounty`
+|`region`|states and provinces|
-* `localadmin`
+|`macrocounty`|a related group of counties. Mostly in Europe.|
-* `locality`
+|`county`|official governmental area; usually bigger than a locality, almost always smaller than a region|
-* `borough`
+|`locality`|towns, hamlets, cities|
-* `region`
+|`localadmin`|local administrative boundaries|
-* `country`
+|`borough`| a local administrative boundary, currently only used for New York City|
+|`neighbourhood`|social communities, neighbourhoods|
+|`coarse`|alias for simultaneously using `country`, `region`, `county`, `locality`, `localadmin`, and `neighbourhood`|
 
 You can also refer to all the administrative hierarchy layers with a single alias, `coarse`.