Content: Student “File Uploader” page fixes

**User story**
As a _student user_, I want the labels to have words spelled out and punctuation at the end of the sentences so that things are more clear.

**Acceptance Criteria**

**Upload your documents section**

- [ ] Revise text “#” to “number”

**Instructions section**

- [ ] Add a “.” (period) at the end of the sentence “Please upload a photo or scanned copy of your documentation.”

- [ ] Add a “.” (period) at the end of the sentence “Rename your document to “FirstnameLastname_[DocumentPurposeName]”.

Screenshot of changes