Syntax highlighting for functions, variables and numbers (#2088)

Supports syntax highlighting for:

- function definitions
- function calls
- numbers
- variables

See issue #1950.

The change for function calls also applies to operation definitions and
to attributes (see bigger example below).
The change for variables also applies to attributes and to imports.

I might be nice to make attributes and imports get their own designated
rules. I can do them as part of this PR, but I think it might be best to
do as a followup issue - because I believe this PR is actually already
an improvement for them.

Simple example for the change (from the original issue description):


![image](https://github.com/user-attachments/assets/cab2630b-0e28-4d48-a98e-7e5bc83e5c7c)

And a bigger example:


![image](https://github.com/user-attachments/assets/7d0c059a-8481-4159-ba64-d8539f1540c0)

vscode/syntaxes/qsharp.tmLanguage.json

@@ -6,6 +6,9 @@
     {
       "include": "#comments"
     },
+    {
+      "include": "#functions"
+    },
     {
       "include": "#keywords"
     },
@@ -20,6 +23,9 @@
     },
     {
       "include": "#strings"
+    },
+    {
+      "include": "#variables"
     }
   ],
   "repository": {
@@ -35,6 +41,103 @@
         }
       ]
     },
+    "functions": {
+      "patterns": [
+        {
+          "comment": "function definition",
+          "name": "meta.function.definition.qsharp",
+          "begin": "\\b(function)\\s+([A-Za-z0-9_]+)(\\()",
+          "beginCaptures": {
+            "1": {
+              "name": "keyword.other.qsharp"
+            },
+            "2": {
+              "name": "entity.name.function.qsharp"
+            },
+            "3": {
+              "name": "punctuation.brackets.round.qsharp"
+            }
+          },
+          "end": "\\)",
+          "endCaptures": {
+            "0": {
+              "name": "punctuation.brackets.round.qsharp"
+            }
+          },
+          "patterns": [
+            {
+              "include": "#comments"
+            },
+            {
+              "include": "#functions"
+            },
+            {
+              "include": "#keywords"
+            },
+            {
+              "include": "#operators"
+            },
+            {
+              "include": "#types"
+            },
+            {
+              "include": "#constants"
+            },
+            {
+              "include": "#strings"
+            },
+            {
+              "include": "#variables"
+            }
+          ]
+        },
+        {
+          "comment": "function calls",
+          "name": "meta.function.call.qsharp",
+          "begin": "\\b(?<!@)([A-Za-z0-9_]+)(\\()",
+          "beginCaptures": {
+            "1": {
+              "name": "entity.name.function.qsharp"
+            },
+            "2": {
+              "name": "punctuation.brackets.round.qsharp"
+            }
+          },
+          "end": "\\)",
+          "endCaptures": {
+            "0": {
+              "name": "punctuation.brackets.round.qsharp"
+            }
+          },
+          "patterns": [
+            {
+              "include": "#comments"
+            },
+            {
+              "include": "#functions"
+            },
+            {
+              "include": "#keywords"
+            },
+            {
+              "include": "#operators"
+            },
+            {
+              "include": "#types"
+            },
+            {
+              "include": "#constants"
+            },
+            {
+              "include": "#strings"
+            },
+            {
+              "include": "#variables"
+            }
+          ]
+        }
+      ]
+    },
     "keywords": {
       "patterns": [
         {
@@ -72,6 +175,11 @@
         {
           "name": "constant.other.result.qsharp",
           "match": "\\b(One|Zero)\\b"
+        },
+        {
+          "comment": "integers and decimals",
+          "name": "constant.numeric.qsharp",
+          "match": "\\b[\\d_]*\\.?[\\d_]\\b"
         }
       ]
     },
@@ -89,6 +197,14 @@
           ]
         }
       ]
+    },
+    "variables": {
+      "patterns": [
+        {
+          "name": "variable.other.qsharp",
+          "match": "\\b(?<!@)[A-Za-z0-9_]+\\b"
+        }
+      ]
     }
   },
   "scopeName": "source.qsharp"