[ios, macos] flesh out iOS runtime styling docs (#6466)

- fixes #5959: MGLBaseStyleLayer docs
- fixes #5960: MGLSource & subclasses docs
- fixes #6467: concrete layer subclass docs
- move Core Graphics include
- slight code & template cleanups
- add ./documentation to git ignores

1 files changed, 16 insertions, 1 deletions

diff --git a/platform/darwin/src/MGLSource.h b/platform/darwin/src/MGLSource.h
index 4d0fd49ea2..bb8f990828 100644
--- a/platform/darwin/src/MGLSource.h
+++ b/platform/darwin/src/MGLSource.h
@@ -1,10 +1,25 @@
 #import <Foundation/Foundation.h>
-#import <CoreGraphics/CoreGraphics.h>
 
+/**
+ A source supplies data to be shown on the map. Sources don't contain styling 
+ details like color or width. Use subclasses of `MGLBaseStyleLayer` to give 
+ visual representation to sources.
+ 
+ You should use the concrete subclasses of `MGLSource` to create vector, 
+ raster, GeoJSON, and other source types.
+ */
 @interface MGLSource : NSObject
 
+/**
+ A string that uniquely identifies the source.
+ */
 @property (nonatomic, copy) NSString *sourceIdentifier;
 
+/**
+ Initializes a source with the given identifier.
+
+ @param sourceIdentifier A string that uniquely identifies the source.
+ */
 - (instancetype)initWithSourceIdentifier:(NSString *)sourceIdentifier;
 
 @end