tomllib: Add shorthand for escape character (TOML 1.1)

Author: hukkin

Lib/test/test_tomllib/data/valid/multiline-basic-str/replacements.json

@@ -0,0 +1,3 @@
+{
+  "escape": {"type":"string","value":"\u001B"}
+}

Lib/test/test_tomllib/data/valid/multiline-basic-str/replacements.toml

@@ -0,0 +1 @@
+escape = "\e"

Lib/tomllib/_parser.py

@@ -49,6 +49,7 @@
         "\\n": "\u000A",  # linefeed
         "\\f": "\u000C",  # form feed
         "\\r": "\u000D",  # carriage return
+        "\\e": "\u001b",  # escape
         '\\"': "\u0022",  # quote
         "\\\\": "\u005C",  # backslash
     }