snippet(latex): add modeline & fix line endings

Amend: #104
Amend: c63094b

Author: itxprashant

latex-mode/int_^

@@ -1,3 +1,4 @@
+# -*- mode: snippet -*-
 # key: int
 # name: int_^
 # condition: (texmathp)
@@ -7,4 +8,4 @@
 }${1:left}${1:$(when (> (length yas-text) 1) "}")
 }${2:$(when (> (length yas-text) 0) "^")
 }${2:$(when (> (length yas-text) 1) "{")
-}${2:right}${2:$(when (> (length yas-text) 1) "}")} $0
+}${2:right}${2:$(when (> (length yas-text) 1) "}")} $0

latex-mode/prod_^

@@ -1,3 +1,4 @@
+# -*- mode: snippet -*-
 # key: prod
 # name: prod_^
 # condition: (texmathp)
@@ -7,4 +8,4 @@
 }${1:i=0}${1:$(when (> (length yas-text) 1) "}")
 }${2:$(when (> (length yas-text) 0) "^")
 }${2:$(when (> (length yas-text) 1) "{")
-}${2:n}${2:$(when (> (length yas-text) 1) "}")} $0
+}${2:n}${2:$(when (> (length yas-text) 1) "}")} $0

latex-mode/sum_^

@@ -1,3 +1,4 @@
+# -*- mode: snippet -*-
 # key: sum
 # name: sum_^
 # condition: (texmathp)
@@ -7,4 +8,4 @@
 }${1:i=0}${1:$(when (> (length yas-text) 1) "}")
 }${2:$(when (> (length yas-text) 0) "^")
 }${2:$(when (> (length yas-text) 1) "{")
-}${2:n}${2:$(when (> (length yas-text) 1) "}")} $0
+}${2:n}${2:$(when (> (length yas-text) 1) "}")} $0