doc: add documentation to all the public structs and enumscmn/doc-all

This makes them show up in the reference, even if the text itself isn't
the most descriptive.

These have been found with

    grep -Przon '\n\ntypedef struct.*?\{' -- include
    grep -Przon '\n\ntypedef enum.*?\{' -- include

1 files changed, 5 insertions, 2 deletions

diff --git a/include/git2/cherrypick.h b/include/git2/cherrypick.h
index dea67c1ff..208166c19 100644
--- a/include/git2/cherrypick.h
+++ b/include/git2/cherrypick.h
@@ -20,14 +20,17 @@
  */
 GIT_BEGIN_DECL
 
+/**
+ * Cherry-pick options
+ */
 typedef struct {
 	unsigned int version;
 
 	/** For merge commits, the "mainline" is treated as the parent. */
 	unsigned int mainline;
 
-	git_merge_options merge_opts;
-	git_checkout_options checkout_opts;
+	git_merge_options merge_opts; /*< Options for the merging */
+	git_checkout_options checkout_opts; /*< Options for the checkout */
 } git_cherrypick_options;
 
 #define GIT_CHERRYPICK_OPTIONS_VERSION 1