removing useless code and imports

src/core/analyzer.rs

@@ -10,9 +10,6 @@ pub struct TokenIter<'a> {
 
 fn append_char_lowercase(c: char, term_buffer: &mut String) {
     term_buffer.push(c.to_ascii_lowercase());
-    // for c_lower in c.to_lowercase() {
-    //     term_buffer.push(c_lower);
-    // }
 }
 
 pub trait StreamingIterator<'a, T> {

src/core/postings.rs

@@ -1,6 +1,5 @@
 use core::schema::DocId;
 use std::ptr;
-use std::collections::BTreeMap;
 use core::schema::Term;
 use core::fstmap::FstMapBuilder;
 use core::index::Segment;

src/core/reader.rs

@@ -9,7 +9,6 @@ use core::schema::DocId;
 use core::index::SegmentComponent;
 use core::simdcompression::Decoder;
 use std::io;
-use std::iter;
 use std::str;
 use core::postings::TermInfo;
 use core::fstmap::FstMap;