Add Docs/Shortcuts.md: list of all notable keyboard shortcuts

Basic shortcuts like keyboard navigation in a textbox, scrolling,
ESC to close modal, ... are not listed

Docs/Shortcuts.md

@@ -0,0 +1,20 @@
+# YAFC keyboard shortcuts
+
+## Global shortcuts
+
+* **Ctrl+S** — Save changes in project.
+* **Ctrl+F** — Find on page.
+* **Ctrl+Z** — Undo last change
+* **Ctrl+Y** or **Ctrl+Shift+Z** — Redo last undo.
+
+## Navigation shortcuts
+
+* **Ctrl+N** — Show NEIE (the Never Enough Items Explorer).
+
+## Tabs shortcuts
+
+* **Ctrl+T** — New production sheet (new tab).
+* **Ctrl+Tab** or **Ctrl+PgDown** — Switch to next tab.
+* **Ctrl+Shift+Tab** or **Ctrl+PgUp** — Switch to previous tab.
+* **Ctrl+Shift+PgDown** — Move current tab right.
+* **Ctrl+Shift+PgUp** — Move current tab left.

Yafc/Data/Tips.txt

@@ -13,3 +13,4 @@ Tip: Specify <number>/m to produce that many items (or fluid units) per minute,
 Tip: Specify <number>b to produce that many belts worth of product, for the belt you've selected in the preferences
 Tip: Specify <number>k to multiply the production by 1000. Other SI prefixes work too! (put the prefix before 'b' or '/h')
 Tip: You can enable the dark mode by clicking on the light-bulb icon on the welcome screen.
+Tip: You can switch between tabs using Ctrl+PgUp or Down and reorder them using Ctrl+Shift+PgUp or Down.