Proof read Regex and add the description how .str is a accessor in pandas

Author: KVHB25

content/regex/regex.ipynb

@@ -6,7 +6,7 @@
    "metadata": {},
    "source": [
     "---\n",
-    "title: Regular Expressions (Fall 2025)\n",
+    "title: Regular Expressions\n",
     "---\n",
     "\n",
     "::: {note} Learning Outcomes\n",
@@ -46,6 +46,8 @@
     "| Membership | `'_' in s` | `ser.str.contains(_)` |\n",
     "| Length | `len(s)` | `ser.str.len()` |\n",
     "\n",
+    "Note that the `.str` method is also an accessor, similar to the `.dt` accessor we discussed in lecture on [Data Cleaning and EDA](https://ds100.org/course-notes/eda/#temporality-with-pandas-dt-accessors).\n",
+    "\n",
     "We'll discuss the differences between Python string functions and `pandas` `Series` methods in the following section on canonicalization.\n",
     "\n",
     "### Canonicalization\n",