Consistency of base language strings

[gujjwal00]

AVNC was translated in few different languages recently. This effort has uncovered some minor inconsistencies in the writing style used for the base language English. While I have tried my best to be concise & clear about the strings used, three is still room for improvement. Its better to do this cleanup now, so that translators too can use a consistent style.

I have looked through some design guidelines , and here is the summary:

• Title Case vs Sentence case: Sentence case seems to be the preferred choice on Android. We are currently using both, so, probably should switch to sentence case in all cases.
• Punctuation: Some of our short strings end with period(.) or exclamation(!). It is recommended to only use them for descriptive texts, so we should remove them.
• Some of the long strings can be simplified using active voice.
• Something else I missed?

This a half announcement/half feedback post, any suggestion is welcome.

cc @zequinh4, @eshagh79, @comradekingu

Resources:
https://material.io/design/communication/writing.html#principles
https://design.firefox.com/photon/copy/capitalization.html
https://design.firefox.com/photon/copy/punctuation.html

[comradekingu]

#41 App strings reworked.