Add link to Wikipedia article on cartographic generalization

Author: nvkelso

CHANGELOG.md

@@ -12,7 +12,7 @@ v1.6.0
   * **boundaries**: Remove `id`, `id:left` and `id:right` properties at low- and mid-zooms (<13), to enable merging. [Issue #1715](https://github.com/tilezen/vector-datasource/issues/1715).
   * **boundaries**: Push `locality` lines down to `min_zoom` **11** (was 10), to reduce file size. [Issue #1715](https://github.com/tilezen/vector-datasource/issues/1715).
   * **boundaries**: Double simplification tolerance. [Issue #641](https://github.com/tilezen/vector-datasource/issues/641) and [PR #1718](https://github.com/tilezen/vector-datasource/pull/1718).
-  * **buildings:** Improve polygon merging at zooms 13, 14, and 15. Remove some mid-zoom content at zoom 13 and 14, and refactor `min_zoom`. Issues [#1686](https://github.com/tilezen/vector-datasource/issues/1686) and [#1732](https://github.com/tilezen/vector-datasource/issues/1732) [PR #1689](https://github.com/tilezen/vector-datasource/pull/1689), [#1704](https://github.com/tilezen/vector-datasource/pull/1704), and [PR #1739](https://github.com/tilezen/vector-datasource/pull/1739)
+  * **buildings:** Improve polygon merging at zooms 13, 14, and 15 including via [aggregation](https://en.wikipedia.org/wiki/Cartographic_generalization#Aggregation) of adjacent features. Remove some mid-zoom content at zoom 13 and 14, and refactor `min_zoom`. Issues [#1686](https://github.com/tilezen/vector-datasource/issues/1686) and [#1732](https://github.com/tilezen/vector-datasource/issues/1732) [PR #1689](https://github.com/tilezen/vector-datasource/pull/1689), [#1704](https://github.com/tilezen/vector-datasource/pull/1704), and [PR #1739](https://github.com/tilezen/vector-datasource/pull/1739)
   * **earth**: Simplify at zoom 8 to match the transition from Natural Earth to OpenStreetMap, significantly reducing file size at that zoom. [Issue #1477](https://github.com/tilezen/vector-datasource/issues/1477) and [PR #1714](https://github.com/tilezen/vector-datasource/pull/1714).
   * **earth**: Truncate `min_zoom` floats to tenths place (and often just ints), to improve merging. [Issue #1477](https://github.com/tilezen/vector-datasource/issues/1477) and [PR #1714](https://github.com/tilezen/vector-datasource/pull/1714).
   * **landuse**: Add `allotments` (community gardens), was already in POIs layer. [PR #1742](https://github.com/tilezen/vector-datasource/pull/1742)