added basic documentation/boilerplate up till ARC_Lexer for the standard library documentation

doc/pages/standard/errno.md

@@ -0,0 +1,63 @@
+\page standard-errno ARC_Errno
+
+*Note: this file is being actively worked on and might change during minor updates*
+
+## About
+
+arc/std/errno.h is used for handling errors as well as printing to debug. It defines a global `uint32_t` ::arc_errno, as well as a global `FILE` ::arc_errno_log_file. For now it just has printing errors, but in the future it is planned to have warnings and general logs added. For error logs to be printed, `ARC_DEBUG` needs to be defined when compiled.
+
+## Basic Error Handling
+
+When throwing errors, ::arc_errno should usually be set to an ARC_ERRNO_ define describing the error. After setting ::arc_errno it is strongly recommended to log that the error happened (this really helps when debugging).
+
+Basic Example:
+```c
+#include <arc/std/errno.h>
+
+void ARC_Example_ThrowNullError(){
+    uint32_t *exampleNumber = NULL;
+
+    if(exampleNumber == NULL){
+        //set arc_errno to the most applicable error
+        arc_errno = ARC_ERRNO_NULL;
+
+        //log where the error happened
+        ARC_DEBUG_LOG_ERROR("ARC_Example_ThrowNullError(), exampleNumber was NULL");
+    }
+}
+```
+
+## Error Handling With More Information
+
+Sometimes the error will have data that could be helpful when debugging, so there is also a log macro that can log the error with variables added. The formatting is the same as printf.
+
+Example With Variables:
+```c
+#include <arc/std/errno.h>
+#include <arc/std/string.h>
+
+void ARC_Example_ThrowPathError(ARC_String *path){
+    ARC_String *data;
+    /* .. try loading data from path here ..  */
+
+    if(data == NULL){
+        //set arc_errno to the most applicable error
+        arc_errno = ARC_ERRNO_DATA;
+
+        //log where the error happened
+        ARC_DEBUG_LOG_ERROR_WITH_VARIABLES("ARC_Example_ThrowPathError(path), path was %s", path->data);
+    }
+}
+```
+
+## Overriding Output File
+
+By default the logs will output to stdout, however this can has an override by defining ARC_DEBUG_LOG_STREAM_OVERRIDE
+
+Example of Overriding Log Stream:
+```c
+//when compiling, ARC_DEBUG_LOG_STREAM_OVERRIDE needs to be set, then just add
+
+//this sets the output to a example_out.txt file that has write permissions
+arc_errno_log_file = fopen("example_out.txt", "w");
+```