Fix uniform_real_distribution_fp16 warning and single Dimension increment

- Change uniform_real_distribution_fp16's arguments to float to avoid maybe-uninitialized warnings in half data type's copy constructor and converter
- Add increment method to Dimensions in order to avoid possible overflows when incrementing single dimensions
- Remove internal_only flag documentation

Resolves: COMPMID-4061

Change-Id: I7c50487193bd7b47b03d52fc595840c7df4e7104
Signed-off-by: Giorgio Arena <giorgio.arena@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/4760
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/utils/Utils.h b/utils/Utils.h
index ca45097..9862514 100644
--- a/utils/Utils.h
+++ b/utils/Utils.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2020 Arm Limited.
+ * Copyright (c) 2016-2021 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -303,7 +303,7 @@
      * @param[in] min Minimum value of the distribution
      * @param[in] max Maximum value of the distribution
      */
-    explicit uniform_real_distribution_fp16(half min = half(0.0), half max = half(1.0))
+    explicit uniform_real_distribution_fp16(float min = 0.f, float max = 1.0)
         : dist(min, max)
     {
     }