Migrating documentation of the ObjectiveC runtime code to appledoc. (#1867)

Work for #1866 

Migrates all the public class docs over to appledoc format.  While Xcode is fine with blank lines in `///` comments, appledoc (used by cocoadocs) isn't and was leaving a bunch of info off the doc pages.

The generator still needs to be updated to do this also; that will be a follow up CL.

1 files changed, 38 insertions, 2 deletions

diff --git a/objectivec/GPBWellKnownTypes.h b/objectivec/GPBWellKnownTypes.h
index 311ac58e..96d51d9e 100644
--- a/objectivec/GPBWellKnownTypes.h
+++ b/objectivec/GPBWellKnownTypes.h
@@ -46,18 +46,54 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-// Extension to GPBTimestamp to work with standard Foundation time/date types.
+/**
+ * Category for GPBTimestamp to work with standard Foundation time/date types.
+ **/
 @interface GPBTimestamp (GBPWellKnownTypes)
+
+/** The NSDate representation of this GPBTimestamp. */
 @property(nonatomic, readwrite, strong) NSDate *date;
+
+/** The NSTimeInterval representation of this GPBTimestamp. */
 @property(nonatomic, readwrite) NSTimeInterval timeIntervalSince1970;
+
+/**
+ * Initializes a GPBTimestamp with the given NSDate.
+ *
+ * @param date The date to configure the GPBTimestamp with.
+ *
+ * @return A newly initialized GPBTimestamp.
+ **/
 - (instancetype)initWithDate:(NSDate *)date;
+
+/**
+ * Initializes a GPBTimestamp with the given NSTimeInterval.
+ *
+ * @param timeIntervalSince1970 Time interval to configure the GPBTimestamp with.
+ *
+ * @return A newly initialized GPBTimestamp.
+ **/
 - (instancetype)initWithTimeIntervalSince1970:(NSTimeInterval)timeIntervalSince1970;
+
 @end
 
-// Extension to GPBDuration to work with standard Foundation time type.
+/**
+ * Category for GPBDuration to work with standard Foundation time type.
+ **/
 @interface GPBDuration (GBPWellKnownTypes)
+
+/** The NSTimeInterval representation of this GPBTimestamp. */
 @property(nonatomic, readwrite) NSTimeInterval timeIntervalSince1970;
+
+/**
+ * Initializes a GPBDuration with the given NSTimeInterval.
+ *
+ * @param timeIntervalSince1970 Time interval to configure the GPBDuration with.
+ *
+ * @return A newly initialized GPBTimestamp.
+ **/
 - (instancetype)initWithTimeIntervalSince1970:(NSTimeInterval)timeIntervalSince1970;
+
 @end
 
 NS_ASSUME_NONNULL_END