Fixes Erroneous syntax highlighting on multiline interface blocks #202, (#203)

while also providing a more elegant solution to commit
a4eaca4
for PR #165.

Author: gnikit

syntaxes/fortran_free-form.tmLanguage.json

@@ -13,6 +13,29 @@
 		"F08"
 	],
 	"firstLineMatch": "(?i)-[*]- mode: fortran free -[*]-",
+	"injections": {
+		"source.fortran.free - ( string | comment )": {
+			"patterns": [
+				{
+					"include": "#line-continuation-operator"
+				}
+			]
+		},
+		"string.quoted.double.fortran": {
+			"patterns": [
+				{
+					"include": "#string-line-continuation-operator"
+				}
+			]
+		},
+		"string.quoted.single.fortran": {
+			"patterns": [
+				{
+					"include": "#string-line-continuation-operator"
+				}
+			]
+		}
+	},
 	"patterns": [
 		{
 			"include": "#preprocessor"
@@ -1553,6 +1576,7 @@
 			]
 		},
 		"control-statements": {
+			"comment": "Statements controlling the flow of the program",
 			"patterns": [
 				{
 					"include": "#assign-statement"
@@ -2173,9 +2197,6 @@
 									"include": "#invalid-word"
 								}
 							]
-						},
-						{
-							"include": "#line-continuation-operator"
 						}
 					]
 				},
@@ -4136,9 +4157,6 @@
 				{
 					"include": "#types"
 				},
-				{
-					"include": "#line-continuation-operator"
-				},
 				{
 					"comment": "Attribute list.",
 					"contentName": "meta.attribute-list.fortran",
@@ -4217,9 +4235,6 @@
 									"include": "#invalid-word"
 								}
 							]
-						},
-						{
-							"include": "#line-continuation-operator"
 						}
 					]
 				},
@@ -4920,9 +4935,6 @@
 			"patterns": [
 				{
 					"include": "#dummy-variable"
-				},
-				{
-					"include": "#line-continuation-operator"
 				}
 			]
 		},
@@ -5020,9 +5032,6 @@
 				},
 				{
 					"include": "#variable"
-				},
-				{
-					"include": "#line-continuation-operator"
 				}
 			]
 		},