[DOC] Follow up reviews to Fern conversion

Start by comparing fern/pages/index.md with fern/pages/introduction.md, focusing on the two cuVS descriptions and the listed core concepts. Check the surrounding terminology and release context, then make the two entry points consistent about vector search, vector compression, and nearest neighbors; the terminology should be unambiguous in both places.

Report bothersome documentation

This is not incorrect, but it bothers me. In the new Fern docs index page fern/pages/index.md

NVIDIA cuVS is a GPU-accelerated library for nearest neighbors, vector compression, and clustering. It provides both core building blocks for constructing new algorithms and end-to-end algorithms that can be used directly or through a growing list of integrations.

NVIDIA cuVS contains state-of-the-art implementations of several algorithms for running approximate and exact nearest neighbors, vector compression, and clustering on the GPU.

I think we should replace 'vector compression' with 'vector search' in both places. Vector compression may be a building block of vector search, but the brand is 'cuVS' not 'cuVC' and so 'vector search' should be right at the starting point where users engage with the docs. If 'vector compression' is seen as an important building block, then I'm fine with it being in the list, but I think 'vector search' should be primary.

If we compare with the list of concepts in fern/pages/introduction.md we see

• Vector Search
• Clustering
• Vector Compression
• Vector Database
• Tuning Indexes

It'd be good if these two places (index and introduction) were rationalized with each other.

Perhaps there's some tension or confusion between whether to use nearest neighbor search or vector search as the primary concept? I see 'nearest neighbors' in the current index page in the two text blocks I pointed out above, but not listed as one of the core concepts in the introduction page.

I'll continue reviewing docs from the recent updates in this issue, but ideally this first concern could be addressed before 26.06 release because it is right at two user entry points for the docs.

To summarize:

1. Please add 'vector search' to the two text blocks noted above in index.md, perhaps keeping 'vector compression' as well
2. Should we mention 'nearest neighbors' in the introduction.md page?