Allow Special Characters in Timeline Field Name Configurations

Under Administration > Timeline > Activity Types : Edit

When creating custom / new fields for timeline entries, there is a limitation on the number of characters allowed in the field title.  Due to this, it would be beneficial to allow a few special characters in the field name to at least include a period . / underscore _ / ampersand & (or allow for a hover to briefly explain what is expected in that field)

One of the things we use timeline entries to capture and report on JO statistics, such as the # opened and the percentage. Due to the only being able to use numbers or letters creating the field name that is descriptive enough, is a big challenge since I have to spell out the words: number / and / percentage (ie. Number and Percent Email Opened (I have to combine both data points in one field as we can only have 15 fields in a timeline entry) it would be nice to put field name as # Emails Opened & % Opened 

I cannot abbreviate number as # nor No. as a period is not allowed, and no without the . could be the word No (opposite of yes)

I cannot abbreviate percentage as % nor pct. as period is not allowed and no one would know what pct is.

Thanks for taking this into consideration