[FEATURE] Searching spinner

[mstawick]

Is your feature request related to a problem? Please describe.
Display indication during async search operations

Describe the solution you'd like
New @Input searching: boolean = false could be added, which would cause a mat-spinner to be displayed as matSuffix, in the place where (x) clear icon is shown

Describe alternatives you've considered
Allow custom styling of the search input field, though this is more complex.

Additional context
When search needs to hit the server and involve debounce on typed in text, it's a much nicer experience when an indication is shown that something is happening.

If you think this can be added, I can code it.

[macjohnny]

sounds good. looking forward to your PR

[macjohnny]

@mstawick this feature was released with version 1.6.0