Update trait summaries for std::fmt

This patch is part of #29355.

Author: brennie

src/libcore/fmt/mod.rs

@@ -427,7 +427,7 @@ impl<'a> Display for Arguments<'a> {
     }
 }
 
-/// Format trait for the `?` character.
+/// `?` formatting.
 ///
 /// `Debug` should format the output in a programmer-facing, debugging context.
 ///
@@ -593,7 +593,7 @@ pub trait Display {
     fn fmt(&self, f: &mut Formatter) -> Result;
 }
 
-/// Format trait for the `o` character.
+/// `o` formatting.
 ///
 /// The `Octal` trait should format its output as a number in base-8.
 ///
@@ -640,7 +640,7 @@ pub trait Octal {
     fn fmt(&self, f: &mut Formatter) -> Result;
 }
 
-/// Format trait for the `b` character.
+/// `b` formatting.
 ///
 /// The `Binary` trait should format its output as a number in binary.
 ///
@@ -687,7 +687,7 @@ pub trait Binary {
     fn fmt(&self, f: &mut Formatter) -> Result;
 }
 
-/// Format trait for the `x` character.
+/// `x` formatting.
 ///
 /// The `LowerHex` trait should format its output as a number in hexadecimal, with `a` through `f`
 /// in lower case.
@@ -735,7 +735,7 @@ pub trait LowerHex {
     fn fmt(&self, f: &mut Formatter) -> Result;
 }
 
-/// Format trait for the `X` character.
+/// `X` formatting.
 ///
 /// The `UpperHex` trait should format its output as a number in hexadecimal, with `A` through `F`
 /// in upper case.
@@ -783,7 +783,7 @@ pub trait UpperHex {
     fn fmt(&self, f: &mut Formatter) -> Result;
 }
 
-/// Format trait for the `p` character.
+/// `p` formatting.
 ///
 /// The `Pointer` trait should format its output as a memory location. This is commonly presented
 /// as hexadecimal.
@@ -828,7 +828,7 @@ pub trait Pointer {
     fn fmt(&self, f: &mut Formatter) -> Result;
 }
 
-/// Format trait for the `e` character.
+/// `e` formatting.
 ///
 /// The `LowerExp` trait should format its output in scientific notation with a lower-case `e`.
 ///
@@ -871,7 +871,7 @@ pub trait LowerExp {
     fn fmt(&self, f: &mut Formatter) -> Result;
 }
 
-/// Format trait for the `E` character.
+/// `E` formatting.
 ///
 /// The `UpperExp` trait should format its output in scientific notation with an upper-case `E`.
 ///