Add keymap to help writing herestrings (#209)

Fixes #203

Author: michaelblyons

Default.sublime-keymap

@@ -0,0 +1,62 @@
+[
+    {
+        "keys": ["\""],
+        "command": "chain",
+        "args": {
+            "commands": [{
+                "command": "insert",
+                "args": {"characters": "\"\n" },
+            }, {
+                "command": "run_macro_file",
+                "args": {"file": "res://Packages/Default/Delete to Hard BOL.sublime-macro"},
+            }, {
+                "command": "insert",
+                "args": {"characters": "\"@" },
+            }, {
+                "command": "move",
+                "args": {"by": "characters", "forward": false},
+            }, {
+                "command": "move",
+                "args": {"by": "characters", "forward": false},
+            }, {
+                "command": "move",
+                "args": {"by": "characters", "forward": false},
+            }],
+        },
+        "context": [
+            { "key": "selection_empty", "match_all": true },
+            { "key": "selector", "operand": "source.powershell - string", "match_all": true },
+            { "key": "preceding_text", "operator": "regex_contains", "operand": "@", "match_all": true },
+        ]
+    },
+    {
+        "keys": ["'"],
+        "command": "chain",
+        "args": {
+            "commands": [{
+                "command": "insert",
+                "args": {"characters": "'\n" },
+            }, {
+                "command": "run_macro_file",
+                "args": {"file": "res://Packages/Default/Delete to Hard BOL.sublime-macro"},
+            }, {
+                "command": "insert",
+                "args": {"characters": "'@" },
+            }, {
+                "command": "move",
+                "args": {"by": "characters", "forward": false},
+            }, {
+                "command": "move",
+                "args": {"by": "characters", "forward": false},
+            }, {
+                "command": "move",
+                "args": {"by": "characters", "forward": false},
+            }],
+        },
+        "context": [
+            { "key": "selection_empty", "match_all": true },
+            { "key": "selector", "operand": "source.powershell - string", "match_all": true },
+            { "key": "preceding_text", "operator": "regex_contains", "operand": "@", "match_all": true },
+        ]
+    },
+]