Contextually Provide Attribute Commit Characters

[TanayParikh]

We should understand the attribute type for both directive attributes and taghelper attributes, and provide the appropriate commit characters ( , :, =, etc.).

[TanayParikh]

After investigation (Thanks @ajaybhargavb for helping clarify different cases / requirements):
Two separate cases:

1. Directive Attributes.
   • No commit characters for indexer attributes. (ends with ... ex. bind-...)
   • Otherwise always provide =
   • Provide if bool property
   • Provide : if parameters present
2. TagHelper Attributes
   • No commit characters for indexer attributes.
   • Otherwise always provide =
   • Provide if bool property