Fix documentation for brace escapes

doc/fd.1

@@ -380,14 +380,16 @@ parent directory
 path without file extension
 .IP {/.}
 basename without file extension
-.IP {{}
-literal '{'
+.IP {{
+literal '{' (an escape sequence)
+.IP }}
+literal '}' (an escape sequence)
 .RE
 
 If no placeholder is present, an implicit "{}" at the end is assumed.
 
-If you need to include the literal text of one of the placeholders, you can use "{{}" to
-escape the first "{". For example "{{}}" expands to "{}", and "{{}{{}}}" expands to "{{}".
+Notice that you can use "{{" and "}}" to escape "{" and "}" respectively, which is especially
+useful if you need to include the literal text of one of the above placeholders.
 
 Examples:
 

src/cli.rs

@@ -808,7 +808,8 @@ impl clap::Args for Exec {
                        '{//}': parent directory\n  \
                        '{.}':  path without file extension\n  \
                        '{/.}': basename without file extension\n  \
-                       '{{}':  literal '{' (for escaping)\n\n\
+                       '{{':   literal '{' (for escaping)\n  \
+                       '}}':   literal '}' (for escaping)\n\n\
                      If no placeholder is present, an implicit \"{}\" at the end is assumed.\n\n\
                      Examples:\n\n  \
                        - find all *.zip files and unzip them:\n\n      \