make casing in docs more consistent (#2524)

* make casing in docs more consistent

* more

* lowercase tantivy

doc/src/avant-propos.md

@@ -2,7 +2,7 @@
 
 > Tantivy is a **search** engine **library** for Rust.
 
-If you are familiar with Lucene, it's an excellent approximation to consider tantivy as Lucene for rust. tantivy is heavily inspired by Lucene's design and
+If you are familiar with Lucene, it's an excellent approximation to consider tantivy as Lucene for Rust. Tantivy is heavily inspired by Lucene's design and
 they both have the same scope and targeted use cases.
 
 If you are not familiar with Lucene, let's break down our little tagline.
@@ -17,7 +17,7 @@ relevancy, collapsing, highlighting, spatial search.
   experience. But keep in mind this is just a toolbox.
   Which bring us to the second keyword...
 
-- **Library** means that you will have to write code. tantivy is not an *all-in-one* server solution like elastic search for instance.
+- **Library** means that you will have to write code. Tantivy is not an *all-in-one* server solution like Elasticsearch for instance.
 
   Sometimes a functionality will not be available in tantivy because it is too
   specific to your use case. By design, tantivy should make it possible to extend
@@ -31,4 +31,4 @@ relevancy, collapsing, highlighting, spatial search.
   index from a different format.
 
   Tantivy exposes a lot of low level API to do all of these things.
-
+

doc/src/basis.md

@@ -11,7 +11,7 @@ directory shipped with tantivy is the `MmapDirectory`.
 While this design has some downsides, this greatly simplifies the source code of
 tantivy. Caching is also entirely delegated to the OS.
 
-`tantivy` works entirely (or almost) by directly reading the datastructures as they are laid on disk. As a result, the act of opening an indexing does not involve loading different datastructures from the disk into random access memory : starting a process, opening an index, and performing your first query can typically be done in a matter of milliseconds.
+Tantivy works entirely (or almost) by directly reading the datastructures as they are laid on disk. As a result, the act of opening an indexing does not involve loading different datastructures from the disk into random access memory : starting a process, opening an index, and performing your first query can typically be done in a matter of milliseconds.
 
 This is an interesting property for a command line search engine, or for some multi-tenant log search engine : spawning a new process for each new query can be a perfectly sensible solution in some use case.
 

doc/src/index_sorting.md

@@ -31,21 +31,21 @@ Compression ratio is mainly affected on the fast field of the sorted property, e
 When data is presorted by a field and search queries request sorting by the same field, we can leverage the natural order of the documents.
 E.g. if the data is sorted by timestamp and want the top n newest docs containing a term, we can simply leveraging the order of the docids.
 
-Note: Tantivy 0.16 does not do this optimization yet.
+Note: tantivy 0.16 does not do this optimization yet.
 
 ### Pruning
 
 Let's say we want all documents and want to apply the filter `>= 2010-08-11`. When the data is sorted, we could make a lookup in the fast field to find the docid range and use this as the filter.
 
-Note: Tantivy 0.16 does not do this optimization yet.
+Note: tantivy 0.16 does not do this optimization yet.
 
 ### Other?
 
 In principle there are many algorithms possible that exploit the monotonically increasing nature. (aggregations maybe?)
 
 ## Usage
 
-The index sorting can be configured setting [`sort_by_field`](https://github.com/quickwit-oss/tantivy/blob/000d76b11a139a84b16b9b95060a1c93e8b9851c/src/core/index_meta.rs#L238) on `IndexSettings` and passing it to a `IndexBuilder`. As of Tantivy 0.16 only fast fields are allowed to be used.
+The index sorting can be configured setting [`sort_by_field`](https://github.com/quickwit-oss/tantivy/blob/000d76b11a139a84b16b9b95060a1c93e8b9851c/src/core/index_meta.rs#L238) on `IndexSettings` and passing it to a `IndexBuilder`. As of tantivy 0.16 only fast fields are allowed to be used.
 
 ```rust
 let settings = IndexSettings {

doc/src/json.md

@@ -39,7 +39,7 @@ Its representation is done by separating segments by a unicode char `\x01`, and
 - `value`: The value representation is just the regular Value representation.
 
 This representation is designed to align the natural sort of Terms with the lexicographical sort
-of their binary representation (Tantivy's dictionary (whether fst or sstable) is sorted and does prefix encoding).
+of their binary representation (tantivy's dictionary (whether fst or sstable) is sorted and does prefix encoding).
 
 In the example above, the terms will be sorted as