Tighten regex for output assertion parsing

The `severity` group was permissive enough to also capture parts of
the message text if that contained any colons. Update it to only capture
(ASCII) words, and update preceding groups to match at least 1
character.

Fixes typeddjango#155

pytest_mypy_plugins/tests/test-regex-assertions.yml

@@ -54,3 +54,18 @@
   main: |
     a = 'hello'
     reveal_type(a)  # NR: .*banana.*
+
+- case: regex_against_callable_comment
+  main: |
+    def foo(bar: str, ham: int = 42) -> set[str | int]:
+      return {bar, ham}
+    reveal_type(foo)  # NR: Revealed type is "def \(bar: builtins\.str, ham: builtins\.int =\) -> .*"
+
+- case: regex_against_callable_out
+  regex: yes
+  main: |
+    def foo(bar: str, ham: int = 42) -> set[str | int]:
+      return {bar, ham}
+    reveal_type(foo)
+  out: |
+    main:3: note: Revealed type is "def \(bar: builtins\.str, ham: builtins\.int =\) -> .*"

pytest_mypy_plugins/utils.py

@@ -326,7 +326,7 @@ def extract_output_matchers_from_out(out: str, params: Mapping[str, Any], regex:
     lines = render_template(out, params).split("\n")
     for line in lines:
         match = re.search(
-            r"^(?P<fname>.*):(?P<lnum>\d*): (?P<severity>.*):((?P<col>\d+):)? (?P<message>.*)$", line.strip()
+            r"^(?P<fname>.+):(?P<lnum>\d+): (?P<severity>[A-Za-z]+):((?P<col>\d+):)? (?P<message>.*)$", line.strip()
         )
         if match:
             if match.group("severity") == "E":