`source:` metatag is case sensitive / DText search links convert search to lowercase

[faucet]

The source: metatag is case sensitive, but a DText search link converts the search string to lowercase - making it impossible to use it to link to source searches containing capital letters. Not sure which should be changed, hence the split issue title, but their behaviour is incompatible with each other.

Steps to reproduce:

• See the results for searching source:*Eipril_Foss* https://e926.net/posts?tags=source%3A*Eipril_Foss*
• Create a DText search link {{source:*Eipril_Foss*}}
• Observe that the link's href is https://e926.net/posts?tags=source%3A%2Aeipril_foss%2A - and gives a different result set.

[Earlopain]

To me it makes more sense to me to make the source search case-insensitive. I think the description is case-insensitive already as well.