pretty-formats: enclose options in angle brackets

Enclose the 'options' placeholders in the documentation of the
%(describe) and %(trailers) format specifiers in angle brackets to
clarify that they are placeholders rather than keywords.

Also remove the indentation from their descriptions, instead of
increasing it to account for the extra two angle brackets in the
headings. The indentation isn't required by asciidoc, it doesn't reflect
how the output text is formatted, and it's inconsistent with the
following bullet points that are at the same level in the output.

Signed-off-by: Andy Koppe <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ak2

Documentation/pretty-formats.txt

@@ -224,13 +224,11 @@ The placeholders are:
 	linkgit:git-rev-list[1])
 '%d':: ref names, like the --decorate option of linkgit:git-log[1]
 '%D':: ref names without the " (", ")" wrapping.
-'%(describe[:options])':: human-readable name, like
-			  linkgit:git-describe[1]; empty string for
-			  undescribable commits.  The `describe` string
-			  may be followed by a colon and zero or more
-			  comma-separated options.  Descriptions can be
-			  inconsistent when tags are added or removed at
-			  the same time.
+'%(describe[:<options>])'::
+human-readable name, like linkgit:git-describe[1]; empty string for
+undescribable commits.  The `describe` string may be followed by a colon and
+zero or more comma-separated options.  Descriptions can be inconsistent when
+tags are added or removed at the same time.
 +
 ** 'tags[=<bool-value>]': Instead of only considering annotated tags,
    consider lightweight tags as well.
@@ -283,13 +281,11 @@ endif::git-rev-list[]
 '%gE':: reflog identity email (respecting .mailmap, see
 	linkgit:git-shortlog[1] or linkgit:git-blame[1])
 '%gs':: reflog subject
-'%(trailers[:options])':: display the trailers of the body as
-			  interpreted by
-			  linkgit:git-interpret-trailers[1]. The
-			  `trailers` string may be followed by a colon
-			  and zero or more comma-separated options.
-			  If any option is provided multiple times the
-			  last occurrence wins.
+'%(trailers[:<options>])'::
+display the trailers of the body as interpreted by
+linkgit:git-interpret-trailers[1]. The `trailers` string may be followed by
+a colon and zero or more comma-separated options. If any option is provided
+multiple times, the last occurrence wins.
 +
 ** 'key=<key>': only show trailers with specified <key>. Matching is done
    case-insensitively and trailing colon is optional. If option is