refactor(BreakingChange): rename method ignore to is_absent

Method `ignore` did not carry its meaning well by the way it is named.
This commit renames it to `is_absent` to clearly state this method
returns whether we have a breaking change.

src/commit/types/breaking_change.rs

@@ -31,7 +31,7 @@ pub enum BreakingChange {
 }
 
 impl BreakingChange {
-    pub fn ignore(&self) -> bool {
+    pub fn is_absent(&self) -> bool {
         matches!(self, BreakingChange::No)
     }
 

src/commit/types/message.rs

@@ -76,7 +76,7 @@ impl ConventionalCommit {
     pub fn first_line_len(&self) -> usize {
         self.commit_type.len()
             + self.scope.header_segment_len()
-            + if self.breaking_change.ignore() { 0 } else { 1 }
+            + if self.breaking_change.is_absent() { 0 } else { 1 }
             + 2 // ": "
             + self.description.len()
     }