Review syntax of documentation

- Add period after every sentence (Roxygen recommendation).
- Use empty lines between function attributes @export, @return, etc.
- Use Markdown where not yet used
- Limit to 80 characters

R/data.R

@@ -1,31 +1,31 @@
-#' Sex choices
-#' 
-#' Allowed values for the sex column in bird metadata
-#' 
+#' Sex choices.
+#'
+#' Allowed values for the sex column in bird metadata.
+#'
 #' @format character vector
 "sex_choices"
 
-#' Species choices
-#' 
-#' Allowed values for the species column in bird metadata
-#' 
+#' Species choices.
+#'
+#' Allowed values for the species column in bird metadata.
+#'
 #' @format character vector
 "species_choices"
 
-#' Tracks validated
-#' 
+#' Tracks validated.
+#'
 #' An example data table containing validated bird tracking data (only 100
 #' records). This is what you can expect after successfully loading and
 #' validating tracking data.
-#' 
+#'
 #' @format data table
 "tracks_validated"
 
-#' Birds validated
-#' 
+#' Birds validated.
+#'
 #' An example data table containing validated bird metadata (only 2 records).
 #' This is what you can expect after successfully loading and validating bird
 #' metadata.
-#' 
+#'
 #' @format data table
-"birds_validated"
+"birds_validated"