javadocs additions/tweaks (#883)

Author: Langston Smith

services-directions/src/main/java/com/mapbox/api/directions/v5/models/MaxSpeed.java

@@ -112,6 +112,7 @@ public abstract static class Builder {
      * Number indicating the posted speed limit.
      *
      * @param speed indicating the posted speed limit
+     * @return a {@link Builder} object
      * @since 3.0.0
      */
     public abstract Builder speed(@Nullable Integer speed);
@@ -120,6 +121,7 @@ public abstract static class Builder {
      * String indicating the unit of speed, either as `km/h` or `mph`.
      *
      * @param unit either as `km/h` or `mph`
+     * @return a {@link Builder} object
      * @since 3.0.0
      */
     public abstract Builder unit(@Nullable String unit);
@@ -128,6 +130,7 @@ public abstract static class Builder {
      * Boolean is true if the speed limit is not known, otherwise null.
      *
      * @param unknown true if speed limit is not known, otherwise null
+     * @return a {@link Builder} object
      * @since 3.0.0
      */
     public abstract Builder unknown(@Nullable Boolean unknown);
@@ -136,6 +139,7 @@ public abstract static class Builder {
      * Boolean is `true` if the speed limit is unlimited, otherwise null.
      *
      * @param none true if speed limit is unlimited, otherwise null
+     * @return a {@link Builder} object
      * @since 3.0.0
      */
     public abstract Builder none(@Nullable Boolean none);

services-speech/src/main/java/com/mapbox/api/speech/v1/MapboxSpeech.java

@@ -18,7 +18,7 @@
 import retrofit2.Call;
 
 /**
- * The Speech API is a text-to-speech APi with a server-side caching layer in front of AWS Polly.
+ * The Speech API is a text-to-speech API with a server-side caching layer in front of AWS Polly.
  * The only requirements are text to dictate, and a Mapbox access token. For 3-step-ahead
  * client-side caching, cache directory is required.
  *