Add gi to go to first non-blank character on line

Fixes #407

README.asciidoc

@@ -472,6 +472,7 @@ Commands beginning with g are used to goto certain position and or buffer:
 
  * `gh`: select to line begin
  * `gl`: select to line end
+ * `gi`: select to line begin (non blank)
 
  * `gg`, `gk`: go to the first line
  * `gj`: go to the last line

doc/manpages/shortcuts.asciidoc

@@ -306,6 +306,7 @@ Changes
 
 Goto Commands
 -------------
+
 If a count is given prior to hitting *g*, *g* will jump to the given line
 
 *gh*::
@@ -314,6 +315,9 @@ If a count is given prior to hitting *g*, *g* will jump to the given line
 *gl*::
 	select to line end
 
+*gi*::
+	select to non blank line start
+
 *gg*, *gk*::
 	go to the first line
 

src/normal.cc

@@ -141,6 +141,9 @@ void goto_commands(Context& context, NormalParams params)
             case 'h':
                 select<mode, select_to_line_begin<true>>(context, {});
                 break;
+            case 'i':
+                select<mode, select_to_first_non_blank>(context, {});
+                break;
             case 'j':
                 context.push_jump();
                 select_coord<mode>(buffer, buffer.line_count() - 1, context.selections());
@@ -233,6 +236,7 @@ void goto_commands(Context& context, NormalParams params)
         "g,k:  buffer top          \n"
         "l:    line end            \n"
         "h:    line begin          \n"
+        "i:    line non blank start\n"
         "j:    buffer bottom       \n"
         "e:    buffer end          \n"
         "t:    window top          \n"

src/selectors.cc

@@ -181,6 +181,14 @@ Selection select_to_line_begin(const Buffer& buffer, const Selection& selection)
 template Selection select_to_line_begin<false>(const Buffer&, const Selection&);
 template Selection select_to_line_begin<true>(const Buffer&, const Selection&);
 
+Selection select_to_first_non_blank(const Buffer& buffer, const Selection& selection)
+{
+    auto it = buffer.iterator_at(selection.cursor().line);
+    skip_while(it, buffer.iterator_at(selection.cursor().line+1),
+               is_horizontal_blank);
+    return {it.coord()};
+}
+
 Selection select_matching(const Buffer& buffer, const Selection& selection)
 {
     Vector<Codepoint> matching_pairs = { '(', ')', '{', '}', '[', ']', '<', '>' };

src/selectors.hh

@@ -40,6 +40,8 @@ Selection select_to_line_end(const Buffer& buffer, const Selection& selection);
 template<bool only_move>
 Selection select_to_line_begin(const Buffer& buffer, const Selection& selection);
 
+Selection select_to_first_non_blank(const Buffer& buffer, const Selection& selection);
+
 enum class ObjectFlags
 {
     ToBegin = 1,