fix: replace 'text' in 'yas-text' in bundled snippets

The previous commit broke these snippets by enabling

snippets/markdown-mode/h1.2

@@ -3,6 +3,6 @@
 # key: h1
 # --
 ${1:Header 1}
-${1:$(make-string (string-width text) ?\=)}
+${1:$(make-string (string-width yas-text) ?\=)}
 
 $0

snippets/markdown-mode/h2.2

@@ -3,6 +3,6 @@
 # key: h2
 # --
 ${1:Header 2}
-${1:$(make-string (string-width text) ?\-)}
+${1:$(make-string (string-width yas-text) ?\-)}
 
 $0

snippets/markdown-mode/ol

@@ -3,4 +3,4 @@
 # key: ol
 # --
 ${1:1}. ${2:Text}
-${1:$(number-to-string (1+ (string-to-number text)))}. $0
+${1:$(number-to-string (1+ (string-to-number yas-text)))}. $0