Auto merge of #23477 - est31:unused_code_removal, r=jdm

Remove unused code (1/N)

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First PR in a series of PRs to remove unused/dead code from servo, powered by an (upcoming) tool of mine. Please take a look and tell me if you want to keep something.

---
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #___ (GitHub issue number if applicable)

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- [ ] There are tests for these changes OR
- [x] These changes do not require tests because they only remove dead code

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components/gfx/text/glyph.rs

@@ -105,8 +105,6 @@ fn is_simple_advance(advance: Au) -> bool {
     }
 }
 
-pub type DetailedGlyphCount = u16;
-
 // Getters and setters for GlyphEntry. Setter methods are functional,
 // because GlyphEntry is immutable and only a u32 in size.
 impl GlyphEntry {

components/gfx/text/text_run.rs

@@ -280,10 +280,6 @@ impl<'a> TextRun {
         self.font_metrics.ascent
     }
 
-    pub fn descent(&self) -> Au {
-        self.font_metrics.descent
-    }
-
     pub fn advance_for_range(&self, range: &Range<ByteIndex>) -> Au {
         if range.is_empty() {
             return Au(0);