Add find shortcut in browser.

README.md

@@ -114,7 +114,7 @@ View.zig       one tab's content: its panes, their layout, and drag handling
 Layout.zig     the split tree: nodes, rearranging, GtkPaned materialization
 Pane.zig       content plus its header, drag source, and drop target
 Terminal.zig   GtkDrawingArea: Cairo/Pango renderer + input handling
-Browser.zig    WebKitWebView plus a back/forward/reload/address bar
+Browser.zig    WebKitWebView plus a nav/address bar and a find bar
 webkit.zig     hand-written bindings for the WebKitGTK calls we make
 Layouts.zig    saved tab templates: model, JSON on disk, {{substitution}}
 OpenLayoutDialog.zig  prompts for a layout's parameters
@@ -369,7 +369,8 @@ in principle, but a terminal grid is small.
 - **Web panes**, on WebKitGTK, sitting in the split tree beside terminals and
   dragging around exactly like they do: back/forward/reload, an address bar
   that takes a URL or falls back to a search, a load-progress indicator in the
-  entry, and the page title feeding the pane header and tab label
+  entry, and the page title feeding the pane header and tab label, plus
+  find-in-page on `Ctrl+F`. See [Find in page](#find-in-page)
 - **Saved layouts**: whole tabs — panes, splits, ratios, per-pane directories
   and scripts — opened in one go, parameterised by `{{name}}`, authored by
   arranging a tab and saving it. See [Layouts](#layouts)
@@ -404,6 +405,7 @@ in principle, but a terminal grid is small.
 | `Ctrl+Shift+V` | paste into a terminal (bracketed-paste aware, refuses unsafe pastes) |
 | `Ctrl+Shift+R` | rename the current tab (empty name = follow the terminal) |
 | `Ctrl+Shift+Z` | zoom the focused pane to fill the tab, and back |
+| `Ctrl+F` | find in the focused web page (web panes only — see [Find in page](#find-in-page)) |
 | `Ctrl+,` | settings |
 | `Ctrl+PageUp/PageDown` | previous / next tab |
 | `Alt+1`..`Alt+8` | jump to tab N, `Alt+9` jumps to the last |
@@ -441,6 +443,26 @@ that zoom is hiding. Closing the zoomed pane leaves zoom; a *different* pane
 closing — a background shell exiting, say — does not, since what you are looking
 at is still there.
 
+## Find in page
+
+`Ctrl+F` in a web pane opens a find bar under its address bar. Typing searches
+as you go — case-insensitively, wrapping at the end of the document — and the
+bar reports how many matches there are, or says there are none and reddens the
+box. `Enter` steps to the next match, `Shift+Enter` to the previous, and the
+two arrow buttons do the same. `Escape` or the × closes the bar, which is also
+what clears the highlighting.
+
+The chord is the browser one rather than this app's usual `Ctrl+Shift`, and it
+is claimed only while a web pane has focus. In a terminal `Ctrl+F` is an
+ordinary control character that the program running there is waiting for —
+forward-a-character in a readline prompt, the prefix key in tmux — so the key
+is left alone there.
+
+WebKit does the searching, and it will only tell you the total number of
+matches, not which one you are on; the count stops at a thousand, on the
+grounds that a page with more matches than that is one where the exact number
+tells you nothing.
+
 ## Tab settings
 
 Right-clicking a tab row opens a small menu: **Rename**, which is the same
@@ -682,8 +704,8 @@ This is a proof of concept, and the following are deliberately absent:
   look right.
 - **Moving panes between tabs.** Panes can only be rearranged within their
   own view.
-- **Browser furniture.** Web panes get navigation and an address bar and
-  nothing else: no bookmarks, history, downloads, devtools, or find-in-page,
+- **Browser furniture.** Web panes get navigation, an address bar and
+  find-in-page, and nothing else: no bookmarks, history, downloads or devtools,
   and each pane uses WebKit's default context, so nothing is persisted between
   runs. Links that ask for a new window are ignored rather than opening a pane.
 - **Restoring a session.** [Startup tabs](#startup-tabs) reopen the