Mattermost-server: Improve help text and error message for choosing username on the signup page

[esethna]

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Notes: Jira ticket

Help text: "You can use lowercase letters, numbers, periods, dashes, and underscores."

https://projects.invisionapp.com/share/B7R4BUHYZCS#/screens/353427679_Recommendation_-_Helper_Text_Improvements

Error message for username that does not meet requirements: "Usernames have to begin with a lowercase letter and be 3-22 characters long. You can use lowercase letters, numbers, periods, dashes, and underscores."

https://projects.invisionapp.com/share/B7R4BUHYZCS#/screens/353633806

[aguywithcode]

I found what appears to be the line I need to change here
https://github.com/mattermost/mattermost-webapp/blob/50c7ae2d31742f207bd7beadded725fc59e84edb/components/signup/signup_email/signup_email.jsx#L273

But that's just for the web app, do we need to change on the mobile apps as well? Is there a centralized string resource dictionary of some sorts that the project uses? How are we handling globalization?

[aguywithcode]

Ahhh...was looking in the wrong place I'm in the right repository now. onward and upward.

[jasonblais]

Glad you found it :) Are you interested taking this help wanted issue?

[lisakycho]

I can take a shot at this!
Are we just changing the visual text for this?

[jasonblais]

@lisakycho Thanks! And that's correct, there are two changes:

1. Updated help text for username on the account creation screen
   

2. Updated error message text for username field
   

[lisakycho]

@hanzei, is there anything else I can do to close this?

[hanzei]

Hey @lisakycho,

I reached out to Eric asking him to review your PR soon. You should get a review on your PR this week. Sorry for the delay.