Merge pull request #4053 from Feoramund/fix-gitignore

Fix `.gitignore`

tests/.gitignore

@@ -0,0 +1,19 @@
+# Ignore all files.
+*
+
+# Un-ignore all directories.
+!*/
+
+# Un-ignore files with an extension.
+#
+# In conjunction with the first two rules, this should catch extensionless
+# binaries on the UNIX-like platforms.
+!*.*
+
+# But remember to ignore executables with an extension.
+*.exe
+*.bin
+
+# Ignore documentation-related files.
+/documentation/verify/
+/documentation/all.odin-doc