Add enum for attention implementations. Fix inconsistency between fuse and unfused TE impls to achieve same performance (removing extra dropout layer in fused layers. Also some minor wording changes

Signed-off-by: tdophung <tdophung@nvidia.com>

[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Signed-off-by: tdophung <tdophung@nvidia.com>

Author: tdophung