Add the small capital letters dead key

It can be added to the keyboard from the settings or into custom layouts
as `accent_small_caps`.

Author: Julow

doc/Possible-key-values.md

@@ -128,6 +128,7 @@ Value                | Meaning
 `accent_horn`        | Horn accent. `ơ`
 `accent_hook_above`  | Hook accent. `ả`
 `accent_double_grave`  | Double grave accent. `ȁ`
+`accent_small_caps`  | Small capital letters. `ᴀ`
 `superscript`        | Superscript. `ᵃ`
 `subscript`          | Subscript. `ₐ`
 `ordinal`            | Turns `a` and `o` into `ª` and `º`.

srcs/compose/accent_small_caps.json

@@ -0,0 +1,28 @@
+{
+  "a": "ᴀ",
+  "b": "ʙ",
+  "c": "ᴄ",
+  "d": "ᴅ",
+  "e": "ᴇ",
+  "f": "ꜰ",
+  "g": "ɢ",
+  "h": "ʜ",
+  "i": "ɪ",
+  "j": "ᴊ",
+  "k": "ᴋ",
+  "l": "ʟ",
+  "m": "ᴍ",
+  "n": "ɴ",
+  "o": "ᴏ",
+  "p": "ᴘ",
+  "q": "ꞯ",
+  "r": "ʀ",
+  "s": "ꜱ",
+  "t": "ᴛ",
+  "u": "ᴜ",
+  "v": "ᴠ",
+  "w": "ᴡ",
+  "x": "x",
+  "y": "ʏ",
+  "z": "ᴢ"
+}