Don't treat - as a word constituent

This produces slightly better results with some string replacements.

CHANGELOG.md

@@ -17,7 +17,8 @@ changed, but on average the results are better.
 
 ### Display
 
-Improved word highlighting in comments when they contain numbers.
+Improved word highlighting in comments when they contain numbers or
+hyphens.
 
 ### Internals
 

sample_files/compare.expected

@@ -29,7 +29,7 @@ sample_files/comma_before.js sample_files/comma_after.js
 e615c73ff860651f7749dc13cb3f110f  -
 
 sample_files/comments_before.rs sample_files/comments_after.rs
-9af41b8c280d4ce94a19023f652e46fb  -
+d5f54a0acc3177939f2720ae5b2679d6  -
 
 sample_files/context_before.rs sample_files/context_after.rs
 eac81f7ca15eff973498a4d8b050ec34  -
@@ -65,7 +65,7 @@ sample_files/hare_before.ha sample_files/hare_after.ha
 2b3a9433cd692d9ffab872477312e3b8  -
 
 sample_files/haskell_before.hs sample_files/haskell_after.hs
-5a2c0c5d4a04f79e2f8f32299e6cd364  -
+0cefa44fdf56edf504f50506bbcded4e  -
 
 sample_files/hcl_before.hcl sample_files/hcl_after.hcl
 24c6205befd0fd1b44f21dd039cafb48  -
@@ -77,7 +77,7 @@ sample_files/helpful_before.el sample_files/helpful_after.el
 a0f2e0115ea94c46d3650ba89b486f09  -
 
 sample_files/html_before.html sample_files/html_after.html
-3d10040707b655920988fae2e610c4be  -
+ed77c9d76eefdc82cf52e089d268ac6c  -
 
 sample_files/html_simple_before.html sample_files/html_simple_after.html
 ce3bfa12bc21d0eb5528766e18387e86  -

src/parse/syntax.rs

@@ -661,7 +661,7 @@ pub fn split_words_and_numbers(s: &str) -> Vec<&str> {
     for (idx, c) in s.char_indices() {
         match word_start {
             Some((start, start_c)) => {
-                if c.is_alphanumeric() || c == '-' || c == '_' {
+                if c.is_alphanumeric() || c == '_' {
                     // Word character, add to the current word if it's
                     // not a number.
                     if c.is_ascii_digit() == start_c.is_ascii_digit() {