feat: Sticky view mode with Z (#719)

book/src/keymap.md

@@ -35,6 +35,7 @@
 | `m`          | Enter [match mode](#match-mode)                    | N/A                         |
 | `:`          | Enter command mode                                 | `command_mode`              |
 | `z`          | Enter [view mode](#view-mode)                      | N/A                         |
+| `Z`          | Enter sticky [view mode](#view-mode)               | N/A                         |
 | `Ctrl-w`     | Enter [window mode](#window-mode)                  | N/A                         |
 | `Space`      | Enter [space mode](#space-mode)                    | N/A                         |
 | `K`          | Show documentation for the item under the cursor   | `hover`                     |
@@ -120,7 +121,10 @@ These sub-modes are accessible from normal mode and typically switch back to nor
 #### View mode
 
 View mode is intended for scrolling and manipulating the view without changing
-the selection.
+the selection. The "sticky" variant of this mode is persistent; use the Escape
+key to return to normal mode after usage (useful when you're simply looking
+over text and not actively editing it).
+
 
 | Key       | Description                                               | Command             |
 | -----     | -----------                                               | -------             |
@@ -130,6 +134,10 @@ the selection.
 | `m`       | Align the line to the middle of the screen (horizontally) | `align_view_middle` |
 | `j`       | Scroll the view downwards                                 | `scroll_down`       |
 | `k`       | Scroll the view upwards                                   | `scroll_up`         |
+| `f`       | Move page down                                            | `page_down`         |
+| `b`       | Move page up                                              | `page_up`           |
+| `d`       | Move half page down                                       | `half_page_down`    |
+| `u`       | Move half page up                                         | `half_page_up`      |
 
 #### Goto mode
 

helix-term/src/keymap.rs

@@ -563,6 +563,22 @@ impl Default for Keymaps {
                 "m" => align_view_middle,
                 "k" => scroll_up,
                 "j" => scroll_down,
+                "b" => page_up,
+                "f" => page_down,
+                "u" => half_page_up,
+                "d" => half_page_down,
+            },
+            "Z" => { "View" sticky=true
+                "z" | "c" => align_view_center,
+                "t" => align_view_top,
+                "b" => align_view_bottom,
+                "m" => align_view_middle,
+                "k" => scroll_up,
+                "j" => scroll_down,
+                "b" => page_up,
+                "f" => page_down,
+                "u" => half_page_up,
+                "d" => half_page_down,
             },
 
             "\"" => select_register,