Add Repeating Characters as a vim til.

vim/repeating-characters.md

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+# Repeating Characters
+
+It's not common to need to type 39 space characters in a row, but when the
+moment arises, you don't want to be caught hitting the space bar 39 times.
+Vim makes it easy. From normal mode, type the number, then `i`, and then the
+character to be repeated followed by an escape.
+
+For instance, for 39 spaces, hit:
+
+```
+39i <esc>
+```
+
+or for 80 dashes, hit:
+
+```
+80i-<esc>
+```